Disabled extract block on single htg
vtkHyperTreeGrid
used to inherit from vtkDataSet
. Since their
internal structure was too different, it was decided to
make it inherit from vtkDataObject
. There was a lot of legacy
mechanism that allowed to use htg as datasets while not fully
being a dataset. vtkSMDataTypeDomain
had a special treatment
for htgs. It is not anymore needed, hence this commit.
Also, filters taking multiblock data set input used to be hard to handled for htgs. There was a little hack that allowed you to consider any htg as multiblock data set, even if filters would discard such input. This is no more needed thanks to the distinction data set / htg.
Fixes #19862 (closed)