Revert "🧪 Use base_ref @ PR base sanity check"

This reverts commit 18091ae.

Author: webknjaz

.github/workflows/reusable-smoke-test.yml

@@ -35,11 +35,8 @@ jobs:
     steps:
     - name: Fail on PRs against illegal branches
       if: >-
-        github.event_name == 'pull_request' &&
-        github.base_ref == format(
-            'refs/heads/{0}',
-            github.event.repository.default_branch
-        )
+        github.event_name == 'pull_request'
+        && github.ref_name == github.event.repository.default_branch
       run: exit 1
 
   fail-fast: