Regression in d961adb866,
it's important that for the Mesh used for undo storage matches
the shape-key instead of using the coordinates of the Basis key.
Prior to bfdbc78466 a different method of
restoring the basis shape-key coordinates was used (restoring from the
input `Mesh.mvert` array). When undo wrote the edit-mesh into the mesh
this was always NULL so the basis shape keys coordinates were never
used.
Now a parameter has been added so undo can use the active shape for the
meshes vertex coordinates.
Reviewed By: sergey
Maniphest Tasks: T96205
Ref D14258