Allow MFA task edits to go through on workboards
Summary: Depends on D20272. Ref T13074. When a task requires MFA to edit, you currently get a fatal. Provide a cancel URI so the prompt works and the edit can go through.
- Locked a task, dragged it on a workboard.
- Before: fatal trying to build an MFA gate.
- After: got MFA gated, answered prompt, action went through.
Reviewed By: amckinley
Maniphest Tasks: T13074
Differential Revision: https://secure.phabricator.com/D20273