bug: matplotlib patch can give a KeyError 'docstring.hardcopy'

[maartenbreddels]

Using glue-solara, if we load a zar file and after that make a 2d image, we get this stacktrace:

Traceback (most recent call last):
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/reacton/ipyvue.py", line 23, in handler
    callback_ref.current(*args)
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/solara/components/button.py", line 84, in <lambda>
    ipyvue.use_event(btn, click_event, lambda *_ignore: on_click and on_click())
                                                                     ^^^^^^^^^^
  File "/Users/maartenbreddels/github/widgetti/glue-solara/glue_solara/app.py", line 276, in add
    add_data_viewer(viewer_type, data_collection[0])
  File "/Users/maartenbreddels/github/widgetti/glue-solara/glue_solara/app.py", line 97, in add_data_viewer
    app.imshow(data=data, show=False)
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/glue_jupyter/app.py", line 433, in imshow
    from .bqplot.image import BqplotImageView
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/glue_jupyter/bqplot/image/__init__.py", line 1, in <module>
    from .layer_artist import *  # noqa
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/glue_jupyter/bqplot/image/layer_artist.py", line 4, in <module>
    from glue.viewers.image.layer_artist import BaseImageLayerArtist, ImageLayerArtist, ImageSubsetArray
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/glue/viewers/image/layer_artist.py", line 22, in <module>
    from glue.viewers.image.frb_artist import imshow
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/glue/viewers/image/frb_artist.py", line 5, in <module>
    from mpl_scatter_density.base_image_artist import BaseImageArtist
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/mpl_scatter_density/__init__.py", line 1, in <module>
    from .scatter_density_artist import *  # noqa
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/mpl_scatter_density/scatter_density_artist.py", line 1, in <module>
    from .generic_density_artist import GenericDensityArtist
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/mpl_scatter_density/generic_density_artist.py", line 4, in <module>
    from .base_image_artist import BaseImageArtist
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/mpl_scatter_density/base_image_artist.py", line 32, in <module>
    class BaseImageArtist(AxesImage):
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/matplotlib/artist.py", line 150, in __init_subclass__
    cls._update_set_signature_and_docstring()
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/matplotlib/artist.py", line 178, in _update_set_signature_and_docstring
    + kwdoc(cls))
      ^^^^^^^^^^
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/matplotlib/artist.py", line 1855, in kwdoc
    if mpl.rcParams['docstring.hardcopy'] else
       ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/maartenbreddels/miniconda3/envs/jdaviz-standalone/lib/python3.11/site-packages/solara/server/patch.py", line 191, in __getitem__
    return self._get_context_dict().__getitem__(key)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
KeyError: 'docstring.hardcopy'

If instead, we first load the w5 dataset, we don't get this error.