When triggering audits, respect committer identities when importing commits
Summary:
Ref T13311. We currently don't use committer identity mappings when triggering audits, so if a user is only associated with an identity via manual mapping we won't treat them as the author.
Instead, use the identity and manual mapping if they're available.
Test Plan:
- Pushed a commit as xyz <xyz@example.org>, an address with no corresponding user.
- In the UI, manually associated that identity with user @alice.
- Ran bin/repository reparse --publish <hash> to trigger audits and publishing for the commit.
- Before: observed the $author_phid was null.
- After: observed the $author_phid is Alice.
Reviewers: amckinley
Reviewed By: amckinley
Maniphest Tasks: T13311
Differential Revision: https://secure.phabricator.com/D20580