[domains] add exit after redirect (#6366)

core/domains/domains.php

@@ -33,6 +33,7 @@
 //redirect admin to app instead
 	if (file_exists($_SERVER["PROJECT_ROOT"]."/app/domains/app_config.php") && !permission_exists('domain_all') && !is_cli()) {
 		header("Location: ".PROJECT_PATH."/app/domains/domains.php");
+		exit;
 	}
 
 //change the domain