Pass unique CommitterIdentity values to PhabricatorRepositoryIdentityQuery
Summary:
DiffusionCommitQuery passed duplicate CommitterIdentity values to PhabricatorRepositoryIdentityQuery, making logs slightly more noisy.
Thus run `array_unique()` before passing.
Closes T16032
Test Plan: Go to http://phorge.localhost/diffusion/commit/query/all/ and look at SQL query in Dark Console before and after applying patch.
Reviewers: O1 Blessed Committers, valerio.bozzolan
Reviewed By: O1 Blessed Committers, valerio.bozzolan
Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Maniphest Tasks: T16032
Differential Revision: https://we.phorge.it/D25964