Summary: ...use the prefab stuff as it does fancier things than we were doing. Only trick then really is to pass username and the map of handle phids => icons to the client so prefab can work nicely. Fixes T4775.
Test Plan: made a herald rule with projects and users. Saw nice icons. Reloaded page and still saw nice icons.
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: epriestley, Korvin
Maniphest Tasks: T4775
Differential Revision: https://secure.phabricator.com/D8749
4b56dbed3a