CI: Adjust pages-alt deployment condition.

Previously it would never fire since the workflow `on` condition
doesn't include pushes. Now, the deployment will happen on PRs
and manual requests.

.github/workflows/ci.yml

@@ -210,7 +210,7 @@ jobs:
     #
     # Caution: GitHub's parsing is weird around multiline expressions so just don't.
     # https://github.community/t/how-to-write-multi-line-condition-in-if/128477
-    if: ${{ github.event_name == 'push' && (github.ref == 'refs/heads/main' || github.ref == 'refs/heads/pages-alt') }}
+    if: ${{ (github.event_name == 'push' && github.ref == 'refs/heads/main') || github.ref == 'refs/heads/pages-alt' }}
 
     steps:
     # This action uses the artifact previously uploaded by actions/upload-pages-artifact