Fix logic for solved/unsolved filtering

[lalvarezt]

nice project btw, very handy
the original logic was not filtering, see below

❯ uv run htb-operator challenge list --category Web --unsolved
╭─ Web ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│  #          ID         Name                                        Difficulty            Avg Difficulty          Points            Solved           Retired            Rating             TODO        Release Date                               │
│  1          1042       Magical Palindrome                          Very Easy             31                        10                ✘                 ✘                4.7                ✘          2025-11-14                                 │
│  2          770        POP Restaurant                              Easy                  41                        30                ✘                 ✘                4.9                ✘          2024-10-11                                 │
│  3          772        Pentest Notes                               Easy                  39                        30                ✘                 ✘                4.6                ✘          2024-10-25                                 │
│  4          828        CDNio                                       Easy                  32                        30                ✘                 ✘                4.2                ✘          2025-01-10                                 │
│  5          854        Dark Runes                                  Easy                  36                        40                ✘                 ✘                4.2                ✘          2025-02-28                                 │
│  6          855        Desires                                     Easy                  45                        40                ✘                 ✘                4.4                ✘          2025-03-07                                 │
│  7          638        JerryTok                                    Medium                51                        50                ✘                 ✘                 5                 ✘          2024-04-19                                 │
│  8          642        ScreenCrack                                 Medium                51                        50                ✘                 ✘                4.9                ✘          2024-05-17                                 │
│  9          645        DoxPit                                      Medium                53                        40                ✘                 ✘                4.8                ✘          2024-05-31                                 │
│  10         755        TornadoService                              Medium                49                        40                ✘                 ✘                4.7                ✘          2024-08-23                                 │
│  11         775        NextPath                                    Medium                50                        30                ✘                 ✘                4.6                ✘          2024-11-08                                 │
│  12         829        Interstellar                                Medium                47                        40                ✘                 ✘                4.8                ✘          2025-01-17                                 │
│  13         863        Dusty Alleys                                Medium                42                        40                ✘                 ✘                4.6                ✘          2025-03-28                                 │
│  14         547        Why Lambda                                  Hard                  58                        60                ✘                 ✘                4.7                ✘          2023-10-06                                 │
│  15         898        SocratesPanel                               Hard                  82                        70                ✘                 ✘                4.6                ✘          2025-05-16                                 │
│  16         735        ArtificialUniversity                        Insane                79                       100                ✘                 ✘                4.8                ✘          2024-06-21                                 │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

❯ htb-operator challenge list --category Web --solved
╭─ Web ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│  #          ID         Name                                        Difficulty            Avg Difficulty          Points            Solved           Retired            Rating             TODO        Release Date                               │
│  1          1042       Magical Palindrome                          Very Easy             31                        10                ✘                 ✘                4.7                ✘          2025-11-14                                 │
│  2          770        POP Restaurant                              Easy                  41                        30                ✘                 ✘                4.9                ✘          2024-10-11                                 │
│  3          772        Pentest Notes                               Easy                  39                        30                ✘                 ✘                4.6                ✘          2024-10-25                                 │
│  4          828        CDNio                                       Easy                  32                        30                ✘                 ✘                4.2                ✘          2025-01-10                                 │
│  5          854        Dark Runes                                  Easy                  36                        40                ✘                 ✘                4.2                ✘          2025-02-28                                 │
│  6          855        Desires                                     Easy                  45                        40                ✘                 ✘                4.4                ✘          2025-03-07                                 │
│  7          638        JerryTok                                    Medium                51                        50                ✘                 ✘                 5                 ✘          2024-04-19                                 │
│  8          642        ScreenCrack                                 Medium                51                        50                ✘                 ✘                4.9                ✘          2024-05-17                                 │
│  9          645        DoxPit                                      Medium                53                        40                ✘                 ✘                4.8                ✘          2024-05-31                                 │
│  10         755        TornadoService                              Medium                49                        40                ✘                 ✘                4.7                ✘          2024-08-23                                 │
│  11         775        NextPath                                    Medium                50                        30                ✘                 ✘                4.6                ✘          2024-11-08                                 │
│  12         829        Interstellar                                Medium                47                        40                ✘                 ✘                4.8                ✘          2025-01-17                                 │
│  13         863        Dusty Alleys                                Medium                42                        40                ✘                 ✘                4.6                ✘          2025-03-28                                 │
│  14         547        Why Lambda                                  Hard                  58                        60                ✘                 ✘                4.7                ✘          2023-10-06                                 │
│  15         898        SocratesPanel                               Hard                  82                        70                ✘                 ✘                4.6                ✘          2025-05-16                                 │
│  16         735        ArtificialUniversity                        Insane                79                       100                ✘                 ✘                4.8                ✘          2024-06-21                                 │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯