Implement "PolicyInterface" on "UserEmail" so "EmailQuery" can load them properly
Allow them to actually load by implementing "PolicyInterface".
Addresses are viewable and editable by the associated user, unless they are a bot/list address, in which case they are viewable and editable by administrators (in preparation for T11860). This has no real impact on anything today.
- Used bin/remove destroy <phid> to destroy an individual email address.
- Before: error while loading the object by PHID in the query policy layer.
- After: clean load and destroy.
Differential Revision: https://secure.phabricator.com/D20927