Restore "Change Status" and "Change Priority" comment actions to Maniphest

Summary: Ref T9132. Supports selects in stacked actions and adds "Change Status" + "Change Priority".

Test Plan: Changed status and priority from stacked actions.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9132

Differential Revision: https://secure.phabricator.com/D14667