R1:16af0d35e510

In Differential, prevent "Accept" and "Reject" from "Plan Changes + Draft"

Summary:
Ref T13130. See PHI483. Currently, "Plan Changes + Draft" uses rules like "Plan Changes", not rules like "Draft", and allows "Accept".

This isn't consistent with how "Draft" and "Accept" work in other cases. Make "Plan Changes + Draft" more like "Draft" for consistency.

Also fix a string that didn't have a natural English version.

Test Plan:
- Added a failing build plan.
- Created a revision.
- Loaded the revision…