`run-staging-report` passes without running code if a commit is pushed before the PR is raised

See here https://app.circleci.com/pipelines/github/ethereum-optimism/superchain-registry/15804/workflows/ec8b96ae-74b9-421c-a8e0-f011123979a9/jobs/97291

I think the pipeline ran before the PR existed, and then it skipped running anything meaningful because it detected it was not a PR. 

This makes it hard to test out our user flows accurately.
