community/jupyer-notebook: upgrade to 6.5.2

Upgrades jupyter-notebook to 6.5.2 and includes a couple other changes:

• Some new aports due to some new dependencies that were added. Hopefully the jupyter ecosystem doesn't continue to get more crazy.
• Removed mathjax2 since it's not being used by anything other than jupyter-nbclassic, and trying the same system vendoring strategy that we're using now for jupyter-notebook ends up resulting in errors.

Notes:

• py3-pytest-tornasync doesn't have a current working release, so the only way to run it is from the tip of their git repository. I do need to fix up the formatting of this APKBUILD once I find an example of the proper git formatting.