Fix camera trigger via MAVLink when camera capture feedback is enabled

- camera_trigger module always publishes the camera_trigger msg (independent of the camera feedback)
- Use camera_trigger msg and set the feedback flag
- Subscribing modules determine if the message is relevant based on the feedback message

src/modules/camera_feedback/CameraFeedback.hpp

@@ -83,4 +83,7 @@ private:
 	uORB::Subscription	_att_sub{ORB_ID(vehicle_attitude)};
 
 	uORB::Publication<camera_capture_s>	_capture_pub{ORB_ID(camera_capture)};
+
+	param_t _p_cam_cap_fback;
+	int32_t _cam_cap_fback{0};
 };