Support ipywidgets >=8

[DManowitz]

This package currently requires ipywidgets <8. However, versions 8.0.0 - 8.0.2 are available.

[banesullivan]

Correct, but there are issues with using ipywidgets >=8. Please reference the following:

• Pyvista using pythreejs no error but not displaying any output: pyvista/pyvista#3360
• pyvista (pythreejs or ipygany backend) incompatible with ipywidgets>7.7.2. pyvista/pyvista#3274
• ipyvtklink plots not visible pyvista/pyvista#3282

I'm currently working on an entirely new notebook rendering backend based on trame over in pyvista/pyvista#3385 and plan on deprecating this library when that is complete. The trame based back-end is *much more performant

Unfortunately, I do not have the bandwidth to fix the issues with the latest ipywidgets but would welcome any community changes to fix it