Fix CI YAML 1.2 schema violation in cache input and optimize build

- Corrected `cache: 'dotnet'` to `cache: true` in `.github/workflows/ci.yml` as `actions/setup-dotnet@v4` expects a boolean for the `cache` input.
- Added `--no-restore` to the `dotnet build` command in the `inspect-code` job to avoid redundant restore operations, as `dotnet restore` is explicitly run in the preceding step.

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

Author: google-labs-jules[bot]

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
         uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "8.0.x"
-          cache: 'dotnet'
+          cache: true
 
       - name: Restore Tools
         run: dotnet tool restore
@@ -34,7 +34,7 @@ jobs:
           key: inspectcode-${{ hashFiles('.config/dotnet-tools.json', '.github/workflows/ci.yml', 'osu.sln*', 'osu*.slnf', '.editorconfig', '.globalconfig', 'CodeAnalysis/*', '**/*.csproj', '**/*.props') }}
 
       - name: Dotnet code style
-        run: dotnet build -c Debug -warnaserror osu.Desktop.slnf -p:EnforceCodeStyleInBuild=true
+        run: dotnet build -c Debug -warnaserror osu.Desktop.slnf -p:EnforceCodeStyleInBuild=true --no-restore
 
       - name: CodeFileSanity
         run: |
@@ -79,7 +79,7 @@ jobs:
         uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "8.0.x"
-          cache: 'dotnet'
+          cache: true
 
       - name: Compile
         run: dotnet build -c Debug -warnaserror osu.Desktop.slnf
@@ -129,7 +129,7 @@ jobs:
         uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "8.0.x"
-          cache: 'dotnet'
+          cache: true
 
       - name: Install .NET workloads
         run: dotnet workload install android wasi-experimental
@@ -150,7 +150,7 @@ jobs:
         uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "8.0.x"
-          cache: 'dotnet'
+          cache: true
 
       - name: Install .NET Workloads
         run: dotnet workload install ios