chore: move TypedDict from typing_extensions to typing

[sebastianliebscher]

SUMMARY

This PR moves TypedDicts from typing_extensions to typing as they are built-in since Python 3.8.

The typing_extensions module serves two related purposes:

Enable use of new type system features on older Python versions. For example, typing.TypeGuard is new in Python 3.10, but typing_extensions allows users on previous Python versions to use it too.
Enable experimentation with new type system PEPs before they are accepted and added to the typing module.

Additionally I

• fixed some spelling
• used walrus := if I found the opportunity and simplified code

TESTING INSTRUCTIONS

unit + integration tests run successfully as code has been simplified. No functionality has been changed.

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[john-bodley]

Thanks for the cleanup @sebastianliebscher.