Blender Git Loki

[#22262] Sculpting shape keys using the Smooth brush switches the shape to the Basis

PBVH used the same verts array as mesh data and shape key/reference key coords
were applying on the mesh data, so on some refreshing undeformed mesh was
displayed.
Added utility functions to get vert coords from key block, apply new vert coords
on keyblock and function to apply coords on bpvh, so now pbvh uses it's ovn
vertex array and no changes are making to the mesh data.

Additional change:
Store key block name in SculptUndoNode, so now shape wouldn't be copied to
wrong keyblock on undo