gh-88965: Fix type substitution of a list of types after initial ParamSpec substitution

[sobolevn]

I've tried to make tests as complete as I can imagine. But, extra cases and suggestions are welcome! ;)

This change has two parts:

1. Collecting type parameters from arguments is changed. Now, we analyze the contents of passes tuples
2. Next, we need to substitute nested tuple. I've reused the existing logic here, but I had to create a method for it

• Issue: Substitution does not work after ParamSpec substitution of the user generic with a list of TypeVars #88965