R1:8bbea6d41c92

Make "Add Action..." add actions at the bottom instead of the top

Summary: Ref T9132. Shhh this never happened shhhhhhh.

Test Plan: Selected multiple actions, saw them add at the bottom.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9132

Differential Revision: https://secure.phabricator.com/D14664