message: Fix: Do not break forward loop when an interface fails to send message
diff: @@ -148,14 +148,18 @@ void MavsdkImpl::forward_message(mavlink_message_t& message, Connection* connect
  if (!targeted_only_at_us && heartbeat_check_ok) {
  std::lock_guard<std::mutex> lock(_connections_mutex);
  + uint succesfull_emissions = 0;
  for (auto it = _connections.begin(); it != _connections.end(); ++it) {
  if ((*it).get() == connection || !(**it).do_forward_messages()) {
  continue;
  }
  - if (!(**it).send_message(message)) {
  - LogErr() << "forward fail";
  + if ((**it).send_message(message)) {
  + succesfull_emissions++;
  }
  }
  + if (succesfull_emissions == 0) {
  + LogErr() << "forward fail";
  + }
  }
  }
  