message: core: remove unused method declaration
diff: @@ -279,8 +279,6 @@ private:
  static bool is_autopilot(uint8_t comp_id);
  static bool is_camera(uint8_t comp_id);
  - void request_autopilot_version();
  -
  void process_heartbeat(const mavlink_message_t& message);
  void process_autopilot_version(const mavlink_message_t& message);
  void process_statustext(const mavlink_message_t& message);
  