Improve type hints

[GilbertYoder]

Sorry for the massive PR 👀

Summary

The aim of this PR is to improve type hints. #95

Fixing some typing errors as well as adding generics

# this
foo: str = None
bar: dict = {}

# becomes (for example)
foo: str | None = None
bar: dict[str, Any] = {}

I used Pyright for type checking. I commited the pyrightconfig.json so my config can be duplicated.

In most places, I could not deduce the correct generics, so Any is used liberally.
Moving forward these could slowly be made more specific.

Behavioral Changes

I did my best to avoid making behavior changes in 99% of cases.

There are a few cases where I introduced changes that could modify behavior. Here are a few:
paddle_billing/Entities/Notifications/NotificationEvent.py:45 -> raise error
paddle_billing/Notifications/Verifier.py:53 -> raise error

paddle_billing/ResponseParser.py:
Two methods were added: get_list and get_dict.
Both of these are just wrappers for get_data but with the correct type annotations. get_dict will still return a list from get_data if the body is None. This should probably be looked at.

paddle_billing/Notifications/Entities/Entity.py & paddle_billing/Notifications/Entities/Simulations/SimulationEntity.py
Added type(entity_class) is not type.

Open to any feedback also.

[davidgrayston-paddle]

Hello 👋

Thank you for contributing these improvements to the SDK!

We should be able to accept these changes once the related test failures are resolved. I've left a few suggestions that should address these failures.

[GilbertYoder]

Thanks for the suggestion. Pushed some changes to fix that.