chore: disable Qt5 builds in CI (#5933)

.github/workflows/test-macos.yml

@@ -24,11 +24,10 @@ jobs:
     strategy:
       matrix:
         os: [macos-13]
-        qt-version: [5.15.2, 6.7.1]
+        qt-version: [6.7.1]
         plugins: [true]
       fail-fast: false
     env:
-      C2_BUILD_WITH_QT6: ${{ startsWith(matrix.qt-version, '6.') && 'ON' || 'OFF' }}
       QT_MODULES: ${{ startsWith(matrix.qt-version, '6.') && 'qt5compat qtimageformats' || '' }}
 
     steps:
@@ -37,11 +36,6 @@ jobs:
         run: |
           echo "C2_PLUGINS=ON" >> "$GITHUB_ENV"
 
-      - name: Set BUILD_WITH_QT6
-        if: startsWith(matrix.qt-version, '6.')
-        run: |
-          echo "C2_BUILD_WITH_QT6=ON" >> "$GITHUB_ENV"
-
       - uses: actions/checkout@v4
         with:
           submodules: recursive
@@ -76,7 +70,6 @@ jobs:
               -DBUILD_APP=OFF \
               -DUSE_PRECOMPILED_HEADERS=OFF \
               -DCHATTERINO_PLUGINS="$C2_PLUGINS" \
-              -DBUILD_WITH_QT6="$C2_BUILD_WITH_QT6" \
               ..
           make -j"$(sysctl -n hw.logicalcpu)"