Steps to reproduce:

1. Go to Alerts -> Media types
2. Create a new Webhook media type
3. In the script field, type return 0 or return []
4. Save media
5. Press the "Test" button to test media

Result:
An error appears in the UI and php runtime error

foreach() argument must be of type array|object, null given [zabbix.php:17 → require_once() → ZBase->run() → ZBase->processRequest() → CController->run() → CControllerMediatypeTestSend->doAction() → error() → CConfigFile->{closure}() in conf/zabbix.conf.php:89]

If return null in the script - the response is 1, not sure if this is correct too.

Expected:
No errors and correct response