Make owners typeahead mostly reasonable
Summary: Ref T8320. Fixes T8427. This is still a little funky because Owners has weird name rules, but should fix the bugs (unselectable packages) in T8427.
Test Plan: Browsed Owners typaheads, used various search functions.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Differential Revision: https://secure.phabricator.com/D13349