Fix model json schema with config types

[NeevCohen]

Change Summary

Fixing an issue where a model would have a field with a default value being a pydantic type (BaseModel, datacalass, TypedDict), then generating the parent model's json schema would fail.

Related issue number

Fix #9253

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

Selected Reviewer: @dmontagu

[codspeed-hq]

CodSpeed Performance Report

Merging #9287 will not alter performance

_{Comparing NeevCohen:fix/model-json-schema-with-config-types (d285b3b) with main (77b0e1c)}

Summary

✅ 13 untouched benchmarks

[NeevCohen]

Please review

[sydney-runkle]

Great work @NeevCohen. Awesome test as well. Merging now, this fix will be included in 2.7.1 soon!