fix: remove return type annotation from settings serializer to fix OpenAPI schema

[zzstoatzz]

Summary

• Removes the -> Any return type annotation from the ser_model() method in PrefectBaseSettings
• Regenerates UI schema with correct type definitions
• Updates UI type references to use non-suffixed schema types

Problem

The @model_serializer(mode='wrap') decorator with a return type annotation (e.g., -> Any) causes Pydantic to generate an empty serialization schema ({}). FastAPI 0.120+ uses serialization mode for response models, which causes types like APISettings to become unknown in the generated TypeScript schema.

Solution

Removing the return type annotation allows Pydantic to fall back to the model schema, producing correct OpenAPI definitions for all settings types. This also removes the need for separate -Input/-Output schema variants.

References

• Request: Ability to specify a model_serializer does not change the serialization JSON Schema. pydantic/pydantic#8791

Test plan

• UI lint passes
• UI type validation passes
• Pre-commit hooks pass
• CI passes

🤖 Generated with Claude Code

[codspeed-hq]

CodSpeed Performance Report

Merging #19616 will not alter performance

_{Comparing fix/settings-serializer-openapi-schema (4103fcb) with main (63d071d)}

Summary

✅ 2 untouched