Fix tests and deprecations, update requirements

[hypadr1v3]

Currently:

• Open3D does not have a release which supports numpy>=2.0.0 and using it would create a segmentation fault in the tests.
• Using arr.ptp() is also deprecated and removed in future numpy releases.
• The PyVista backend also does not support the Panel feature anymore (as shown here) so that option is removed.
• Tests were also broken which were fixed with adding an __init__.py to all relevant places. With this commit, all tests pass with one xfail (on .laz decompression) and warnings for deprecations which are fixed in other PRs.