Add typing_extensions for backwards compatibility

[Matt Huisman (matthuisman)]

PR: #22741 switched to importing TypedDict and Literal in two different files which has broken Python 3.7 (they added to typing in 3.8)

This PR reverts those changes back to using typing_extensions

related issue:
#23179

[Matt Huisman (matthuisman)]

@microsoft-github-policy-service agree

[Matt Huisman (matthuisman)]

suspect this import here may also have failed without the sys.path change?

[Karthik Nadig (karthiknadig)]

Matt Huisman (@matthuisman) Thanks for the PR. We need to discuss internally about supporting 3.7 as it is no longer in support upstream.

[Matt Huisman (matthuisman)]

was breaking 3.7 intentional?
I see the PR that made this change didn't remove other typing_extensions so looks to me like a mistake
Also nothing in the release notes etc :)

Be nice if there could be warning about it and some time for users to migrate etc

[Karthik Nadig (karthiknadig)]

Matt Huisman (@matthuisman) We have announced this in our release notes and blogs:

• July 2023: https://devblogs.microsoft.com/python/python-in-visual-studio-code-july-2023-release/#upcoming-deprecation-of-python-3-7-support#upcoming-deprecation-of-python-3-7-support
• October 2023: https://devblogs.microsoft.com/python/python-in-visual-studio-code-october-2023-release/#deprecation-of-python-3-7-support

pytest dropped support as well:

We typically leave things as is until there is a change in underlying tools that we depend on. In this case, pytest dropped support for 3.7 we no longer need to preserve support for it in the testing features. For anyone who want to use python extension with 3.7 can pin the python extension version to the one where we still had support.

Python versions will drop on schedule and it is published here: https://devguide.python.org/versions/

[Luciana Abud (luabud)]

Hey Matt Huisman (@matthuisman), first of all, thank you so much for being interested in contributing to our extension! However, based on the comments above, we'll close this PR. In our contributing guide we specify that we may reject a PR for issues that don't have the "needs PR" label, like the issue linked in this PR. I apologize for this frustration but I hope this doesn't discourage you from submitting more contributions!

[Oleksandr Yatsuk (oleksandr-yatsuk)]

PySpark extensively uses Python 3.7 for example.
This change breaks all testing functionality on many dev machines

[Karthik Nadig (karthiknadig)]

You can pin python extension to older version.

pyspark has also dropped 3.7 support:

[Karthik Nadig (karthiknadig)]

Please use "Install another Version" from the extension view to pin the extension to previous version.

Python 3.7 has been out of support for over 6 months. We don't plan on restoring support for out of service version of python.