Menus: Simplify the test for `wp_update_nav_menu_item()` with special characters in category name.

The `menu-item-title` value is saved as a `post_title` property, so the resulting property can be checked directly, without a callback.

Follow-up to [48416].

See #48011.
Built from https://develop.svn.wordpress.org/trunk@48439


git-svn-id: https://core.svn.wordpress.org/trunk@48208 1a063a9b-81f0-0310-95a4-ce76da25c4cd