Remove unused apps from the DocumentType typeahead

Summary: Ref T10951. This diff removes uninstalled applications from the result set for DocumentType restults

Test Plan: Uninstall an application (diviner for example), then go to the document type search menu and ensure that the uninstalled application doesn't show up.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley

Maniphest Tasks: T10951

Differential Revision: https://secure.phabricator.com/D16445