[check-enforcer] Change runner from ubuntu-latest to ubuntu-slim (#49577)

Author: mikeharder

.github/workflows/check-enforcer.yml

@@ -21,7 +21,7 @@ jobs:
       pull-requests: read # to read pull requests; use "write" for response comments (azure/azure-sdk-actions)
       checks: read # to read check status (azure/azure-sdk-actions)
     name: "[TEST-IGNORE] Check Enforcer (${{ github.event_name }}:${{ github.event.action }})"
-    runs-on: ubuntu-latest # This image is intentionally set to "latest", and not to a specific version
+    runs-on: ubuntu-slim
     steps:
       - uses: azure/azure-sdk-actions@e1ab1a2cb5944bfea74b5cdbfc96e34da96548d2
         with: