Blender Git Loki

Sculpt: Option to not modify hidden Face Sets in Face Sets Edit

This options allows to perform Face Sets operations while preserving the
mesh visibility. Edit hidden face sets is enabled by default in order to
expand the visible area of the mesh with the grow/shrink operator, but
this can be changed in the keymap per edit operation as more operations
are supported.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8029