[Bug]: Pydantic models with overridden Config fail to parse with extra=ignore

[r4victor]

It turns out that overriding Config in pydantic models breaks pydantic-duality extra=ignore parsing since Config overrides both Model.__request__.Config and Model.__response__.Config. As a result, adding new fields to models with custom Config leads to old client / new server incompatibility (and many models define custom schema_extra).

pydantic-duality supports defining common Config for all models via generate_dual_base_model(Config). As we want to also have a CoreModel with common config and methods, the fix would involve generating a custom base core model with custom config on the fly for every model that needs custom config:

class _BaseRunConfigurationConfig(CoreModel.Config):
        @staticmethod
        def schema_extra(schema: Dict[str, Any]):
            ...

class BaseRunConfiguration(generate_dual_core_model(_BaseRunConfigurationConfig)):
   ...

The inheritance approach should also be reworked so that mixin models do not inherit from CoreModel.