Fix mobile action menus in Phriction

Summary: Fixes T6963. Long term will likely make this more like other document views, but not worth the time right now since this is only location.

Test Plan: Review Phriction document at desktop and mobile breakpoints. Click menu and see menu.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6963

Differential Revision: https://secure.phabricator.com/D11420