Route Maniphest comments/detail edits through new code
Summary: Ref T2217. When you add comments (or use that interface to make updates), ship it through the new code.
Test Plan: Added comments, made other changes to Maniphest tasks.
Reviewers: btrahan
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T2217
Differential Revision: https://secure.phabricator.com/D7088