Revert some changes from commit d05948fa
Keep changes of labels for seed_source proxies and test updates
Point Source -> Point Cloud High Resolution Line Source -> Line Source
Revert changes of proxy names.
Since now we have are just changes to the labels, only backwards compatibility code for Python has been added.
Co-authored-by: Yohann Bearzi firstname.lastname@example.org
Follow on to !4074 (merged).
Closes #16960 (closed)