Prevent "Manage" profile menu items from being hidden

Summary: Ref T10054. Prevent users from removing this item and locking themselves out of the system unless they can guess the URI.

Test Plan: Tried to disable "Manage", wasn't permitted to.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10054

Differential Revision: https://secure.phabricator.com/D15113