R1:e27a83960c2e

Send Maniphest transaction preview through new code

Summary: Ref T2217. Get rid of this rendering pathway's internals and move them to the modern stuff.

Test Plan: See screenshot.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2217

Differential Revision: https://secure.phabricator.com/D7072