Werk #13211: Fix 'only from' monitoring in Check_MK services for systemd hosts

The Check_MK service did not report the only-from configuration if the used super server was systemd and the socket unit name did not start with 'check-mk-agent'. This can either be the case if you are using the Checkmk raw edition, or you have changed the agent package name via the WATO.

While the only-from setting was enforced correctly, the agent did not report it back to the monitoring server.

If the agent reports back the effective only-from, the monitoring server will compare it to the configured value, and issues a WARNING if the allowed IP addresses deviate from the expected ones.

To the list of all Werks