DepreciationWarning in toolbar causes AttributeError

[raphaelquast]

Describe the issue

Accessing toolbar properties causes AttributeError: 'super' object has no attribute '__getattr__'

The problematic lines are here:

https://github.com/matplotlib/ipympl/blob/238d7965c52f3fe8de02242c096714e064847819/ipympl/backend_nbagg.py#L162-L170

This is most probably caused by the mixin-style classes ... a explanation (and a possible solution) might be this:

https://stackoverflow.com/a/28864246/9703451

Versions

 3.11.3 | packaged by conda-forge | (main, Apr  6 2023, 08:50:54) [MSC v.1934 64 bit (AMD64)]
ipympl version: 0.9.3