The menu items for `users.php` and `profile.php` that require the `promote_users` cap should be wrapped in an `is_multisite()` conditional a la `user-new.php`.

Props SergeyBiryukov.
Fixes #30526.


git-svn-id: https://develop.svn.wordpress.org/trunk@30659 602fd350-edb4-49c9-b593-d223f7449a82