When there is a non-sculpt mode undo step before the operation,
redoing the node tool operation doesn't work correctly-- the undo
that happens before repeating the operator doesn't work.
The fix is using the sculpt geometry undo step system. Theoretically
this should be cheap because implicit sharing will avoid copying most
of the attribute layers. However in the future it would be good to avoid
a PBVH rebuild after the operation in some cases.
0f9dcafa76