guard benchmark action with performance label again

This check was removed in #2774 for simplicity, bring it back to spam less

.github/workflows/benchmark.yml

@@ -19,6 +19,7 @@ concurrency:
 
 jobs:
  benchmark:
+ if: github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'performance')
  runs-on: ubuntu-latest
 
  steps: