Summary: Fixes T7118. This does the basic "filter the list" thing, though it ends up being a little manual since I guess this hasn't come up before? There is also potential weird behavior if the user was using an app and lost access to it - they will have nothing selected on edit - but I think this is actually correct behavior in this circumstance.
Test Plan:
used a user who couldn't get access to the "quick create" apps and noted that the dropdown list on dashboard panel create was missing the expected engines
ran `arc unit --everything` to verify abstract method implemented everywhere
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T7118
Differential Revision: https://secure.phabricator.com/D11687
5a9df1a225