When workflow dialog buttons are clicked, disable the button
This might have some weird side effects but we should normally never need to re-use a workflow dialog form so it's not immediately obvious that this can break anything.
- Added sleep(1) to the Mute controller and the Maniphest task controller.
- Added phlog(...) to the Mute controller.
- Opened the mute dialog, mashed the button a thousand times.
- Before: Saw a bunch of logs.
- After: Button immediately disables, saw only one log.
Differential Revision: https://secure.phabricator.com/D19246