Websites php version gets (accidentally) altered by admin if websites php version is client_id != 0

Summary

If a website uses a php version only available to the customer/owner of the site and alterations are made by the admin, the php version gets overwritten by the admin on saving any changes.

I'am not sure if I got that right - but I think the function "getserverphp" in interface/web/sites/ajax_get_json.php does not even accomodate the possibility of "client-only php versions", from within the admins view. There is a query (line 86-93) specific to the admin, but "$app->functions->intval($client['client_id']" won't yield any other result than "0" when this is queried by the admin. So most of the admin specific part is not working as intended.

Environment

Server OS + version: irrelevant
ISPConfig version: all