Use a policy-aware query for Project typeahead

Summary: Fixes T2677. Currently, you can typeahead projects you can't see.

Test Plan: Typeahead'ed projects. Verified active projects appeared; archived did not.

Reviewers: chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T2677

Differential Revision: https://secure.phabricator.com/D5242