resolver: skip restart if disabled.

[demisrael]

While resolver service disabled, on "restart all services" it try and fail

◐  Restarting 'kaspa-resolver'                                                                                                                                                                        

Failed to restart kaspa-resolver.service: Unit kaspa-resolver.service not found.

▲  command ["sudo", "-kS", "-p", "", "systemctl", "restart", "kaspa-resolver"] exited with code 5
│
■  command ["sudo", "-kS", "-p", "", "systemctl", "restart", "kaspa-resolver"] exited with code 5
│  
■  Io(Custom { kind: Other, error: "command [\"sudo\", \"-kS\", \"-p\", \"\", \"systemctl\", \"restart\", \"kaspa-resolver\"] exited with code 5" })