Make "Audit Requested" put commits into the "Needs Audit" state

Summary: Fixes T7504. I think that task legitimately describes a bug and that the current behavior is counterintuitive.

Test Plan: Manually added an auditor to a commit with none; saw it become "Audit Required" as an overall state.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T7504

Differential Revision: https://secure.phabricator.com/D17185