Users: Limit the scope of admin files required in `WP_REST_Users_Controller`.

This requires only `wp-admin/includes/user.php` for `get_editable_roles()`, instead of `wp-admin/includes/admin.php`.

Follow-up to [43589].

Props johnwatkins0.
Fixes #49450.
Built from https://develop.svn.wordpress.org/trunk@47299


git-svn-id: http://core.svn.wordpress.org/trunk@47099 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php

@@ -1210,8 +1210,8 @@ class WP_REST_Users_Controller extends WP_REST_Controller {
 				);
 			}
 
-			// Include admin functions to get access to get_editable_roles().
-			require_once ABSPATH . 'wp-admin/includes/admin.php';
+			// Include user admin functions to get access to get_editable_roles().
+			require_once ABSPATH . 'wp-admin/includes/user.php';
 
 			// The new role must be editable by the logged-in user.
 			$editable_roles = get_editable_roles();

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.4-beta1-47298';
+$wp_version = '5.4-beta1-47299';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.