Clean up Multirow Manager UI
Summary: Fixes T4234 (Policy and Herald). I will have an additional diff for Maniphest Batch Editor, which looks jank in many other ways.
Test Plan:
Test editing a policy and some herald rules. Stuff lines up better.
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T4234
Differential Revision: https://secure.phabricator.com/D10864