Add support for descriptors as model fields

[nickyoung-github]

Change Summary

Add support for descriptors as model fields. Check newly-introduced __pydantic_descriptor_fields__ to determine whether to get/set fields via __dict__ or __getattribute__/__setattr__

• Introduce get_model_dict() and set_model_dict(), which get/set descriptor fields which handling __dict__
• Change get_inner_value() to supplement attrs with descriptor values, if present

Note that this change can be released standalone, but will not on its own enable all the functionality to fix the pydantic/pydantic issue. That also requires this pydantic/pydantic change.

Related issue number

pydantic/pydantic Issue
pydantic/pydantic Pull Request

Checklist

• Unit tests for the changes exist
• Documentation reflects the changes where applicable
• Pydantic tests pass with this pydantic-core (except for expected changes)
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

Selected Reviewer: @sydney-runkle

[codecov]

Codecov Report

Attention: Patch coverage is 68.00000% with 24 lines in your changes missing coverage. Please review.

Project coverage is 89.51%. Comparing base (ab503cb) to head (07beacc).
Report is 265 commits behind head on main.

Files with missing lines	Patch %	Lines
src/validators/model.rs	70.96%	18 Missing ⚠️
src/serializers/type_serializers/model.rs	53.84%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1592      +/-   ##
==========================================
- Coverage   90.21%   89.51%   -0.71%     
==========================================
  Files         106      112       +6     
  Lines       16339    17916    +1577     
  Branches       36       40       +4     
==========================================
+ Hits        14740    16037    +1297     
- Misses       1592     1859     +267     
- Partials        7       20      +13     

Files with missing lines	Coverage Δ
src/serializers/type_serializers/model.rs	91.25% <53.84%> (-2.63%)	⬇️
src/validators/model.rs	91.44% <70.96%> (-6.38%)	⬇️

... and 61 files with indirect coverage changes

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[codspeed-hq]

CodSpeed Performance Report

Merging #1592 will not alter performance

_{Comparing nickyoung-github:main (07beacc) with main (562fad3)}

Summary

✅ 157 untouched benchmarks

[nickyoung-github]

Please review

[nickyoung-github]

This is my first submission attempt for pydantic-core. I've tried to follow all the guidelines but please forgive (and educate!) me if I missed anything