message: core: fix requests for CAMERA_IMAGE_CAPTURED
  When sending MAV_CMD_REQUEST_MESSAGE for CAMERA_IMAGE_CAPTURED we not
  only have to look at param1 but also param2. That way we don't re-send a
  request if we're already in the process of doing so.
diff: @@ -106,14 +106,15 @@ private:
  struct CommandIdentification {
  uint32_t maybe_param1{0}; // only for commands where this matters
  + uint32_t maybe_param2{0}; // only for commands where this matters
  uint16_t command{0};
  uint8_t target_system_id{0};
  uint8_t target_component_id{0};
  bool operator==(const CommandIdentification& other) const
  {
  - return maybe_param1 == other.maybe_param1 && command == other.command &&
  - target_system_id == other.target_system_id &&
  + return maybe_param1 == other.maybe_param1 && maybe_param2 == other.maybe_param2 &&
  + command == other.command && target_system_id == other.target_system_id &&
  target_component_id == other.target_component_id;
  }
  @@ -139,7 +140,12 @@ private:
  identification.command = command.command;
  if (command.command == MAV_CMD_REQUEST_MESSAGE ||
  command.command == MAV_CMD_SET_MESSAGE_INTERVAL) {
  - identification.maybe_param1 = static_cast<uint32_t>(std::lround(command.params.param1));
  + const uint32_t param1 = static_cast<uint32_t>(std::lround(command.params.param1));
  + identification.maybe_param1 = param1;
  + if (param1 == MAVLINK_MSG_ID_CAMERA_IMAGE_CAPTURED) {
  + identification.maybe_param2 =
  + static_cast<uint32_t>(std::lround(command.params.param2));
  + }
  }
  identification.target_system_id = command.target_system_id;
  identification.target_component_id = command.target_component_id;
  