Abilities API: Ensure public method is used in the codebase

Discovered when syncing code back to Abilities API repository in WordPress/abilities-api#126.

Follow-up to [61032].
See #64098.



git-svn-id: https://develop.svn.wordpress.org/trunk@61059 602fd350-edb4-49c9-b593-d223f7449a82

Author: gziolo

src/wp-includes/abilities-api/class-wp-abilities-registry.php

@@ -121,8 +121,7 @@ public function register( string $name, array $args ): ?WP_Ability {
 
 		// Validate ability category exists if provided (will be validated as required in WP_Ability).
 		if ( isset( $args['category'] ) ) {
-			$category_registry = WP_Ability_Categories_Registry::get_instance();
-			if ( ! $category_registry->is_registered( $args['category'] ) ) {
+			if ( ! wp_has_ability_category( $args['category'] ) ) {
 				_doing_it_wrong(
 					__METHOD__,
 					sprintf(