Can't extract type for valid providers from provider registry

[AndrewIngram]

Description

If I create a provider registry, I can't extract the actual list of valid models:

It works as expected when I interact with the registry directly:

But if I want to wrap the API and pass the model to it, I lose the type-safety:

Is there a more appropriate way to extract this type, or do the types in the library need to be adjusted to make this more feasible?