message: core: only get the UUID once
diff: @@ -201,6 +201,11 @@ bool DeviceImpl::send_message(const mavlink_message_t &message)
  void DeviceImpl::request_autopilot_version()
  {
  + if (_target_uuid_initialized) {
  + // Already initialized, we can exit.
  + return;
  + }
  +
  if (!_autopilot_version_pending && _target_uuid_retries >= 3) {
  // We give up getting a UUID and use the system ID.
  