Don't require project edit permission to create a project with members other than yourself

Summary: See PHI193. Previously, see similar D18763. Skip this legacy-style policy check when creating a project, since we know you can add members, even if the policy doesn't actually resolve in your favor.

Test Plan:

• Created a project with edit policy "Members of project" and myself, plus any other user (so the code goes down this path, not the "join/leave" path) as members.

Differential Revision: https://secure.phabricator.com/D19169