Test Plan:
Added CC's/Auditors, clicked the form elements, and saw correct
behaviour. Verified that metadata was present in the detail table.
Reviewers: epriestley
Reviewed By: epriestley
CC: aran, epriestley, 20after4, Koolvin
Maniphest Tasks: T904
Differential Revision: https://secure.phabricator.com/D2002
