Fix for sculpt mode: invert visible hides all faces with Multires modifier #95419
Grids face indices should not change on the fly based on hidden state.
It caused the rendering glitches shown on the original bug report and the attached recordings.
* this PR removes the unnecessary check and dependency of grids visibility with the smooth/sharp of faces.
* replaces smooth flag for sharp flag which better express the intent and simplifies the logic.
Pull Request: https://projects.blender.org/blender/blender/pulls/121929
8182ebd4d2