Make project menus unconditionally configurable

Summary: Fixes T10213. I think the "Edit" item was originally conditional (or maybe I just forgot to add that part), but that got dropped when we swapped how it worked. This is all stable now anyway and can be available without needing prototypes enabled.

Test Plan: Edited a project menu.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10213

Differential Revision: https://secure.phabricator.com/D15117