Don't require edit capability on the Favorites application to edit personal menu items

Summary:
Ref T11096. Currently, editing ProfileMenuItemConfigurations always requires that you can edit the corresponding object.

This is correct for global items (for example: you can't change the global menu for a project unless you can edit the project) but not for personal items.

For personal items, only require that the user can edit the customPHID object. Today, this is always their own profile.

Test Plan: As a non-admin, edited personal menu items.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11096

Differential Revision: https://secure.phabricator.com/D17228