Depends on D19898. Ref T13222. See PHI873. Allow objects to opt into an "MFA is required for all edits" mode.
Put tasks in this mode if they're in a status that specifies it is an mfa status.
This is still a little rough for now:
- There's no UI hint that you'll have to MFA. I'll likely add some hinting in a followup.
- All edits currently require MFA, even subscribe/unsubscribe. We could maybe relax this if it's an issue.