Bump VTK to 9.6 to fix Surface Nets problem

[MattTheCuber]

Closes #13

Notable Changes

• Surface Nets inverted internal faces bug was fixed (see https://gitlab.kitware.com/vtk/vtk/-/issues/19156)
  • Removed the need to fill voids in testing and examples
• Surface Nets mean mesh time dropped from to 9.28 seconds to 0.45 seconds
  • This raised the mean relative repair time from 3.35% to 87.83%
• No impact on accuracy (maintained a 100% success rate)

[github-actions]

Coverage for Python 3.13 on windows-latest

File	Stmts	Miss	Cover	Missing
edge_mender
__init__.py	2	0	100%
data_factory.py	132	0	100%
edge_mender.py	159	0	100%
geometry_helper.py	43	0	100%
mesh_generator.py	70	0	100%
visualizer.py	46	0	100%
TOTAL	452	0	100%

[MattTheCuber]

Currently testing on 10K random 10x10x10 datasets:

[MattTheCuber]

All passed btw:

[MattTheCuber]

Turns out this still fails with trimesh>4.9.0

[MattTheCuber]

Disregard, I had to comment out

https://github.com/MattTheCuber/edge-mender/blob/master/edge_mender/mesh_generator.py#L111-L114