[BUG]: `kwargs` input to ether tagged methods

[shababo]

Sadly we failed recently when trying to handle ether tagged methods that have a kwargs input. This severely limits the external integration feature (i.e. integrating ether only through a yaml config and no decorators and touching of integrated source code).

I bet we can do it. It may be something as simple as custom logic around the Pydantic validation/introspection stuff in the func wrappers.