Fix readability of tutorials in dark mode

[kushalbakshi]

This PR fixes the readability of the Jupyter Notebook outputs in the Using the json type tutorials. This resolves issue 1078.

Below are the screenshots from local testing after applying changes to the code as seen in this PR:
Dark mode - the font in the tables previously appeared white, and was therefore, not readable. See linked issue above for images.

Light mode - there was no issue here previously and remains the same as before.

[guzman-raphael]

@kushalbakshi Thanks for patching this! 💪

Dark mode users (:raising_hand_man:) will certainly appreciate this improvement. Providing some small suggestions but otherwise agree with the approach here.

[kushalbakshi]

Hi @guzman-raphael, I'm finally getting the chance to get back on this one.

Here is one example each of black background with white text, and black text with white background. Let me know what you prefer. I think the black background is cleaner in dark mode, but it's up to you.

[guzman-raphael]

Thanks @kushalbakshi. That is an interesting option. 🤔

Just discussed this with @kabilar to get his opinion and he agreed with me that the white background one is cleaner. Let's proceed with that.

[kushalbakshi]

Thanks @kushalbakshi. That is an interesting option. 🤔

Just discussed this with @kabilar to get his opinion and he agreed with me that the white background one is cleaner. Let's proceed with that.

Sounds good! The changes have been tested and committed here.

Something to note - the docs container would not build without the typing-extensions package. There was a ModuleNotFoundError. I've added that to docs/.docker/pip_requirements.txt. Here's the error message I received prior to adding this requirement:

docs-docs-1  |   File "/opt/conda/lib/python3.9/site-packages/mkdocstrings/plugin.py", line 41, in <module>
docs-docs-1  |     from typing_extensions import ParamSpec
docs-docs-1  | ModuleNotFoundError: No module named 'typing_extensions'
docs-docs-1 exited with code 1

[kushalbakshi]

Commenting to record that I was able to remove the typing-extensions module from pip_requirements.txt. It must've been patched in the dependencies of the packages we use for docs. This is now ready for review