Fix non-public capabilities in Application edit
Summary: Ref T603. I nuked this check by accident and neglected to test the negative case.
Test Plan: Saved a non-public policy (Herald Global) and a public policy (Maniphest View).
Reviewers: asherkin, btrahan
Reviewed By: asherkin
CC: aran
Maniphest Tasks: T603
Differential Revision: https://secure.phabricator.com/D7278