update pr-auditor to run on ready to review

Created by: davejrt

updates the auditor to run when a PR to moved from draft to ready to review.

Anecdotally I've seen a bunch of PR's ready for review without a pr-auditor status because they were initially submitted as drafts.

Still an on going effort to resolve https://github.com/sourcegraph/sourcegraph/issues/35635

Test plan

a green run on this PR