(fix): use typing_extensions for NamedTuple

[ilan-gold]

I was off on the version in my comment or we just missed I meant "greater than": python/cpython#92027

In any case, we can just use typing_extensions: python/typing_extensions#44

Previously, this was causing issues with 3.10 as this was the case not covered (this feature broke in 3.9, but is fixed in 3.11, and we special cased <3.10).

• Closes #
• Tests added
• Release note added (or unnecessary)

[ilan-gold]

Hmmm, I thought typing_extensions was either already a dependent or included in python. Better not to add a dependency just for this.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.19%. Comparing base (e0b81f1) to head (37bb47f).
Report is 70 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1593      +/-   ##
==========================================
- Coverage   86.70%   84.19%   -2.52%     
==========================================
  Files          37       37              
  Lines        5974     5966       -8     
==========================================
- Hits         5180     5023     -157     
- Misses        794      943     +149     

Files with missing lines	Coverage Δ
src/anndata/_settings.py	93.70% <100.00%> (-0.34%)	⬇️

... and 8 files with indirect coverage changes