CI: Add a step to ensure the Qt chrome can compile on macOS

The AppKit chrome is now the default, but the Qt chrome may still be
enabled for testing. Let's ensure it can compile in CI, as it has
already broken since the default change.

Meta/Azure/Lagom.yml

@@ -168,6 +168,23 @@ jobs:
           SERENITY_SOURCE_DIR: '$(Build.SourcesDirectory)'
           QT_QPA_PLATFORM: 'offscreen'
 
+    - ${{ if and(eq(parameters.fuzzer, 'NoFuzz'), eq(parameters.os, 'macOS') ) }}:
+      - script: |
+          set -e
+          cmake -B Build -DENABLE_QT=ON
+        displayName: 'Enable the Ladybird Qt chrome'
+        workingDirectory: $(Build.SourcesDirectory)/Meta/Lagom
+        env:
+          CCACHE_DIR: '$(SERENITY_CCACHE_DIR)'
+
+      - script: |
+          set -e
+          cmake --build .
+        displayName: 'Build Ladybird Qt chrome'
+        workingDirectory: $(Build.SourcesDirectory)/Meta/Lagom/Build
+        env:
+          CCACHE_DIR: '$(SERENITY_CCACHE_DIR)'
+
     - ${{ if eq(parameters.lagom_lints, true) }}:
       - script: |
           set -e