mavlink: reciever trajectory_representation_waypoints resepect valid_points

- fixes https://github.com/PX4/PX4-Autopilot/issues/18369

src/modules/mavlink/mavlink_receiver.cpp

@@ -1917,10 +1917,9 @@ MavlinkReceiver::handle_message_trajectory_representation_waypoints(mavlink_mess
 
 	vehicle_trajectory_waypoint_s trajectory_waypoint{};
 
-	trajectory_waypoint.timestamp = hrt_absolute_time();
-	const int number_valid_points = trajectory.valid_points;
+	const int number_valid_points = math::min(trajectory.valid_points, vehicle_trajectory_waypoint_s::NUMBER_POINTS);
 
-	for (int i = 0; i < vehicle_trajectory_waypoint_s::NUMBER_POINTS; ++i) {
+	for (int i = 0; i < number_valid_points; ++i) {
 		trajectory_waypoint.waypoints[i].position[0] = trajectory.pos_x[i];
 		trajectory_waypoint.waypoints[i].position[1] = trajectory.pos_y[i];
 		trajectory_waypoint.waypoints[i].position[2] = trajectory.pos_z[i];
@@ -1936,17 +1935,12 @@ MavlinkReceiver::handle_message_trajectory_representation_waypoints(mavlink_mess
 		trajectory_waypoint.waypoints[i].yaw = trajectory.pos_yaw[i];
 		trajectory_waypoint.waypoints[i].yaw_speed = trajectory.vel_yaw[i];
 
-		trajectory_waypoint.waypoints[i].type = UINT8_MAX;
-	}
-
-	for (int i = 0; i < number_valid_points; ++i) {
 		trajectory_waypoint.waypoints[i].point_valid = true;
-	}
 
-	for (int i = number_valid_points; i < vehicle_trajectory_waypoint_s::NUMBER_POINTS; ++i) {
-		trajectory_waypoint.waypoints[i].point_valid = false;
+		trajectory_waypoint.waypoints[i].type = UINT8_MAX;
 	}
 
+	trajectory_waypoint.timestamp = hrt_absolute_time();
 	_trajectory_waypoint_pub.publish(trajectory_waypoint);
 }