Put "Projects" edit field back on Basics management panel for repositories

Summary: Ref T10923. Fixes T10955. This was accidentally excluded when I broke the form into pages.

Test Plan: Saw edit field in panel; changed project tags for a repository.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10923, T10955

Differential Revision: https://secure.phabricator.com/D15896