[Python.NET] Wrap in interface (#1240)

Hello, This PR changed behavior of pythonnet to use stricter typing when a method returns an interface. I'd like a way to opt-out of this behavior, and I'll share a representative use-case below. The tl;dr is that python is a dynamic language

[Python.NET] Re: Wrap in interface (#1240)

The original bug report described a similar problem, except the behavior without defaulting to stricter interface types is very unintuitive. Imagine you have a well documented library, that exposes property Prop of type IInterface. When specific class implements some Method  in IInterface explicitl