[ty] Fix bug where ty would think that a `Callable` with a variadic positional parameter could be a subtype of a `Callable` with a positional-or-keyword parameter (#23610)
## Summary
On `main`, this assertion fails, but it should pass:
```py
from ty_extensions import static_assert, is_subtype_of, is_assignable_to
from typing import Protocol
class A(Protocol):
def __call__(self, *args: int | str): ...
class B(Protocol):
def __call__(self, a: int): ...
static_assert(not is_assignable_to(A, B))
```
A variadic positional parameter can never satisfy a
positional-or-keyword parameter, because the former can never be passed
a keyword argument, whereas the latter can.
This fixes the only remaining conformance-suite failure on
`callables_subtyping.py`.
## Test Plan
mdtests
---------
Co-authored-by: Claude <noreply@anthropic.com>
ruff
9afd1ebd - [ty] Fix bug where ty would think that a `Callable` with a variadic positional parameter could be a subtype of a `Callable` with a positional-or-keyword parameter (#23610)
