fix(security): Mark recording_servers key appconfig as private as it contains a secret

Signed-off-by: Joas Schilling <coding@schilljs.com>

lib/private/AppConfig.php

@@ -112,6 +112,7 @@ class AppConfig implements IAppConfig {
 		'spreed' => [
 			'/^bridge_bot_password$/',
 			'/^hosted-signaling-server-(.*)$/',
+			'/^recording_servers$/',
 			'/^signaling_servers$/',
 			'/^signaling_ticket_secret$/',
 			'/^signaling_token_privkey_(.*)$/',