message: core: don't create system for telemetry radio
  SiK radios inject TELEMETRY_RADIO into the stream. However, it doesn't
  quite make sense to create a system just for these.
  In the future we should make use of the information but for now I think
  it's best to just ignore it.
diff: @@ -325,6 +325,13 @@ void MavsdkImpl::receive_message(mavlink_message_t& message, Connection* connect
  }
  }
  + if (!found_system && message.compid == MAV_COMP_ID_TELEMETRY_RADIO) {
  + if (_message_logging_on) {
  + LogDebug() << "Don't create new system just for telemetry radio";
  + }
  + return;
  + }
  +
  if (!found_system) {
  make_system_with_component(message.sysid, message.compid);
  }
  