moved $userModel in isAdmin

app/Libraries/Aauth.php

@@ -540,13 +540,13 @@ class Aauth
 	 */
 	public function isAdmin(int $userId = null)
 	{
-		$userModel = new UserModel();
-
 		if (! $userId)
 		{
 			$userId = (int) @$this->session->user['id'];
 		}
 
+		$userModel = new UserModel();
+
 		return $this->isMember($this->config->groupAdmin, $userId);
 	}