Summary: 'cuz those can be complicated. Fixes T4738. I needed to do a fair amount of heavy lifting to get the policy stuff rendering correctly. For now, I made this end point very one purpose and tried to make that clear.
Test Plan: looked at some custom policies. see screenshots.
Reviewers: chad, epriestley
Reviewed By: epriestley
Subscribers: epriestley, Korvin
Maniphest Tasks: T4738
Differential Revision: https://secure.phabricator.com/D8890
