R1:3c5a17ba8a55

Restore "Reclaim" and "Abandon" actions to Differential on EditEngine

Summary: Ref T11114. This begins restoring comment actions to Differential, but on top of EditEngine.

Test Plan: {F2263148}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11114

Differential Revision: https://secure.phabricator.com/D17107