✨ Enable Pydantic's serialization mode for responses, add support for Pydantic's `computed_field`, better OpenAPI for response models, proper required attributes, better generated clients (#10011)
* ✨ Enable Pydantic's serialization mode for responses
* ✅ Update tests with new Pydantic v2 serialization mode
* ✅ Add a test for Pydantic v2's computed_field