refactor: Wrap GitHub CI conditionals in curly braces (#5796)

This change wraps all GitHub conditionals in `${{ .. }}`, both for consistency and to reduce unexpected failures, because it was previously noticed that not all conditionals work without those curly braces.

.github/workflows/on-pr.yml

@@ -92,12 +92,12 @@ jobs:
 
   check-levelization:
     needs: should-run
-    if: needs.should-run.outputs.go == 'true'
+    if: ${{ needs.should-run.outputs.go == 'true' }}
     uses: ./.github/workflows/check-levelization.yml
 
   build-test:
     needs: should-run
-    if: needs.should-run.outputs.go == 'true'
+    if: ${{ needs.should-run.outputs.go == 'true' }}
     uses: ./.github/workflows/build-test.yml
     strategy:
       matrix:
@@ -111,7 +111,7 @@ jobs:
     needs:
       - should-run
       - build-test
-    if: needs.should-run.outputs.go == 'true'
+    if: ${{ needs.should-run.outputs.go == 'true' }}
     uses: ./.github/workflows/notify-clio.yml
     secrets:
       clio_notify_token: ${{ secrets.CLIO_NOTIFY_TOKEN }}