Fix CI CS0103 DifficultyRating errors in osu ruleset checks

Agent-Logs-Url: https://github.com/winnerspiros/osu/sessions/33b6c84a-b773-490d-9dc3-68523fc6ea67

Co-authored-by: winnerspiros <1675249+winnerspiros@users.noreply.github.com>

Author: Copilot

osu.Game.Rulesets.Osu/Edit/Checks/CheckLowDiffOverlaps.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Checks.Components;
 using osu.Game.Rulesets.Objects;

osu.Game.Rulesets.Osu/Edit/Checks/CheckTimeDistanceEquality.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Checks.Components;
 using osu.Game.Rulesets.Objects;