When any label is added to a PR, the workflow was re-running and causing issues
because the E2E check would fail for non-ready-for-e2e labels.
This change removes 'labeled' from the trigger types entirely. Users can now:
1. Add the ready-for-e2e label to a PR
2. Click 'Re-run all jobs' in GitHub Actions UI to trigger E2E tests
This is simpler and avoids the complexity of trying to maintain previous check
status when non-E2E labels are added.
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>