Python upgrades

Summary

This merge request upgrades to Python 3.11 (#1000 (closed)) now that it's safely bedded in, and:

• switches from pydantic to typedload (#929 (closed)) as it's cleaner and works better with static typing
• upgrades python dependencies

Checklist

• Documentation impact considered
• Manual smoke test run (if possible)
• Local-only tests run
• Assigned related ticket to reviewer