Revert removal of label requirement

Author: samlitowitz

.github/workflows/pipes.yaml

@@ -30,7 +30,7 @@ jobs:
     if: |
       github.event_name == 'push'
         || github.event_name == 'workflow_dispatch'
-        || github.event_name == 'pull_request'
+        || (github.event_name == 'pull_request' && contains(github.event.pull_request.labels.*.name, 'ci'))
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4