Improve danger-review to work without a token

What does this MR do?

Also, adds needs: [] so that it starts immediately.

Testing this in gitlab-org/gitlab-development-kit!2316 (diffs).

Screenshots

Tested via a fork splattael/gitlab-styles!1 (closed).

No token	With token

Added by @splattael 😅

Check-list

• Verify the change in all affected pipelines.