revert removeal of Sheild's User class

src/Controllers/RegisterController.php

@@ -19,6 +19,7 @@
 use CodeIgniter\HTTP\RequestInterface;
 use CodeIgniter\HTTP\ResponseInterface;
 use CodeIgniter\Shield\Authentication\Authenticators\Session;
+use CodeIgniter\Shield\Entities\User;
 use CodeIgniter\Shield\Exceptions\ValidationException;
 use CodeIgniter\Shield\Models\UserModel;
 use CodeIgniter\Shield\Traits\Viewable;