05d6818aa2
When trying to sculpt a Grease Pencil object with a line art modifier
(other modifiers probably also casue issues), Blender would crash.
I wasn't able to track down the exact issue but it's related to how
the update-cache stores pointers to original data.
This reverts part of e2befa425a to not make use of the update
cache while sculpting. Combined with modifiers, this approach
is just too unstable right now.
Pull Request: https://projects.blender.org/blender/blender/pulls/114410