Access to `points` should be suppressed in PCL code

[kunaltyagi]

Access to points can also be suppressed in a lot of places.

Originally posted by @SergioRAgostinho in #4190

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My observations:

points usage can be removed in following ways:

• replace with functions like: copyPointCloud instead of copyPoint
• replace with functions like isNormalFinite
• replace points. to use functions of PointCloud

#4217, #4218, #4219, #4221 tackle third type to a large extent

[kshitijgoel007]

Just FYI: This actually breaks compatibility with ROS meta package perception_pcl (branch: melodic-devel). Specifically, if you transform a ROS point cloud message to pcl::PointCloudpcl::PointXYZ object with the pcl_conversions header in that package, and then send it to transformPointCloud, the lack of .points actually leads to a segfault.

[kunaltyagi]

Could you give more details please? Is this a bug in PCL or a bug in perception_pcl's conversion?

[kshitijgoel007]

I realized later that perception_pcl has just not updated with this change done in PCL. Apologies, should have posted that here.

[kunaltyagi]

Oops, closed accidentally. But essentially, point raised is not an issue