Attach json schema for Pydantic Models in `get_stream_configuration()`

When we call `get_stream_configuration()`, we create a dict with metatdata related to each stream including the type. Type information is deduced from the connected function's return type. If the return type is a pydantic model, however, we return the string representation of that model since the client recipient can't deserialize it if it doesn't have the associated dependency required to understand the model.

What we should do instead is return a json schema associated with that model either *instead-of* or *in-addition-to* the annotated return type. Returning the json schema provides full information into a nested dictionary-like object, which means it's likely more detailed than, let's say, annotating a function's return type with just `dict`.