Comment the pointcloud transformation example

It appeared in the documentation and it's not ported.

ros2/README.md

@@ -53,5 +53,5 @@ To help get you started on your software development, here are examples of nodes
 | 13 | [Align to ArUco](align_to_aruco.md)                                                      |  Detect ArUco fiducials using OpenCV and align to them.|
 | 14 | [Deep Perception](deep_perception.md)                                                    |  Use YOLOv5 to detect 3D objects in a point cloud.|
 | 15 | [Avoiding Race Conditions and Deadlocks](avoiding_deadlocks_race_conditions.md)          | Learn how to avoid Race Conditions and Deadlocks |
-<!--| 11 | [PointCloud Transformation](example_11.md)      |  Convert PointCloud2 data to a PointCloud and transform to a different frame.| 
+<!--| 11 | [PointCloud Transformation](example_11.md)      |  Convert PointCloud2 data to a PointCloud and transform to a different frame.| -->