Let project prefilling accept PHIDs

Summary: I recently made this better about accepting project names, but we use it in some cases with PHIDs. Make that work properly again.

Test Plan: Clicked "New Task" from a project page.

Reviewers: chad, btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D8778