feat: introduce typeddicts for request objects

[armandobelardo]

This PR makes it so that we create TypedDict clones for any object we have, e.g. aliases of objects, objects, unions and undisc unions. These clones are stored in a requests module alongside the other types, and are used in the method signatures for our SDK methods.

Generally the architecture is:

• typeddict.py - general construction and utilities for understanding if something can be a typeddict, snippets, etc.
• Whenever we get a Reference now, you can specify if that reference is used in a request -- if so, we then check if the SDK is using TypedDicts and handle retrieving the appropriate reference for the type (e.g. if it can be a typeddict, and you're in a request, and have typeddicts enabled, then we get the reference for the type in the requests module)
  • This happens through the plumbing of as_request and use_typeddict_requests
• Constructing TypedDicts side-saddles existing Pydantic model creation, see object_generator.py, etc. -- we effectively gather a list of fields and then pass that to the pydantic_model.py, as well as typeddict.py such that both model forms get created
• Snippets for TypedDicts side-saddle the existing snippet infra, similar to model construction, see ObjectSnippetGenerator in object_generator.py as an example

Seed run: #4128