message: core: remove unused variable
diff: @@ -814,8 +814,6 @@ MAVLinkCommands::Result SystemImpl::make_command_msg_rate(uint16_t message_id,
  return MAVLinkCommands::Result::UNKNOWN_ERROR;
  }
  - MAVLinkCommands::CommandLong command_msg_rate{};
  -
  command.command = MAV_CMD_SET_MESSAGE_INTERVAL;
  command.params.param1 = float(message_id);
  command.params.param2 = interval_us;
  