pyvista: extract_cells filter does not keep text fields.

The picking method with visible_pick_call_back does not keep text fields in arrays anymore.

The visible_pick_call_back depends on extract_cells, line 162 in picking.py:

picked.append(smesh.extract_cells(cids_to_get))

after this line, all my text arrays are stripped. I noticed that I had to remove .decode() in my code because text arrays are not binary anymore in pyvista, so it may have to do with that change. I use text arrays to recover the name and category of the data picked (top app categories, not pyvista data types).