CI: Update actions to latest versions, use default runner .NET version

.github/workflows/android_builds.yml

@@ -21,7 +21,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Set up Java 17
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@v4
         with:
           distribution: temurin
           java-version: 17

.github/workflows/linux_builds.yml

@@ -116,12 +116,6 @@ jobs:
       - name: Setup python and scons
         uses: ./.github/actions/godot-deps
 
-      - name: Set up .NET Sdk
-        uses: actions/setup-dotnet@v3
-        if: ${{ matrix.build-mono }}
-        with:
-          dotnet-version: '6.0.x'
-
       - name: Setup GCC problem matcher
         uses: ammaraskar/gcc-problem-matcher@master