Use `wp_get_admin_notice` and `wp_admin_notice` to handle multisite settings notices. Props costdev. See #57791. Built from https://develop.svn.wordpress.org/trunk@56409 git-svn-id: http://core.svn.wordpress.org/trunk@55921 1a063a9b-81f0-0310-95a4-ce76da25c4cd