bad-argument-count false positive with unpacking

### Describe the Bug

Reproducer:

```
def f(x, y, z): ...

def test(xs: list[int]):
f(*xs[-4:-2], 42)
```

Output:

```
ERROR Expected 3 positional arguments, got 4 in function `f` [bad-argument-count]
--> /tmp/foo.py:4:17
|
4 | f(*xs[-4:-2], 42)
| ^^
|
INFO 1 error
```

Even though `xs[-4:-2]` has no more than 2 elements (with indices -4 and -3).

### Sandbox Link

_No response_

### (Only applicable for extension issues) IDE Information

_No response_