Correct type of kwargs in assertpy.exception.ExceptionMixin.when_called_with (#13903)

The keys of `kwargs` dicts are always strings, the type hint is for the values,
which in this case could be anything.

Author: allanlewis

stubs/assertpy/assertpy/exception.pyi

@@ -5,4 +5,5 @@ __tracebackhide__: bool
 
 class ExceptionMixin:
     def raises(self, ex: type[BaseException] | BaseException) -> Self: ...
-    def when_called_with(self, *some_args: Any, **some_kwargs: dict[str, Any]) -> Self: ...
+    # The types of some_args and some_kwargs must equal the types of the called function.
+    def when_called_with(self, *some_args: Any, **some_kwargs: Any) -> Self: ...