Add coerce_numbers_to_str option in str_schema

[NeevCohen]

Change Summary

Add coerce_numbers_to_str option in str_schema to support per-field configuration as requested in pydantic/pydantic#8383

Related issue number

pydantic/pydantic#8383

Checklist

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

[codecov]

Codecov Report

Merging #1249 (6cc9989) into main (ab503cb) will decrease coverage by 0.55%.
Report is 50 commits behind head on main.
The diff coverage is 100.00%.

❗ Current head 6cc9989 differs from pull request most recent head 4a9cdf9. Consider uploading reports for the commit 4a9cdf9 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1249      +/-   ##
==========================================
- Coverage   90.21%   89.67%   -0.55%     
==========================================
  Files         106      108       +2     
  Lines       16339    17061     +722     
  Branches       36       41       +5     
==========================================
+ Hits        14740    15299     +559     
- Misses       1592     1742     +150     
- Partials        7       20      +13     

Files	Coverage Δ
python/pydantic_core/core_schema.py	94.66% <ø> (-0.10%)	⬇️
src/validators/string.rs	99.37% <100.00%> (+0.03%)	⬆️

... and 28 files with indirect coverage changes

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[codspeed-hq]

CodSpeed Performance Report

Merging #1249 will not alter performance

_{Comparing NeevCohen:feature/coerce-numbers-to-str-in-str-schema (4a9cdf9) with main (0830d0d)}

Summary

✅ 152 untouched benchmarks

[sydney-runkle]

Amazing work! Now just needs the pydantic counterpart :)