Fix issue with recursive generic models

[Viicos]

Change Summary

Fixes #11748. Although this bug was present since v2.0, it manifested in a hard failure since 2.11, so we'll backport it.

Related issue number

Checklist

• The pull request title is a good summary of the changes - it will be used in the changelog
• Unit tests for the changes exist
• Tests pass on CI
• Documentation reflects the changes where applicable
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

[cloudflare-workers-and-pages]

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[github-actions]

Coverage report

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File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
pydantic/_internal
_generate_schema.py
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[codspeed-hq]

CodSpeed Performance Report

Merging #11775 will not alter performance

_{Comparing recursive-gen (eda3702) with main (bf06866)}

Summary

✅ 46 untouched benchmarks