R1:4887c6aa803d

Allow "transaction.search" to be constrained by PHIDs

Summary: Depends on D19046. Ref T11330. Supports querying for specific transactions while responding to webhooks.

Test Plan: Called `transaction.search` with and without PHID constraints.

Maniphest Tasks: T11330

Differential Revision: https://secure.phabricator.com/D19047