False positive when calling overloaded `*args` with union of tuples

Code sample in [pyright playground](https://pyright-play.net/?reportUnreachable=true&code=GYJw9gtgBALgngBwJYDsDmUkQWEMpgBuApiADZgCGAJgFC0ACRpFNt1xwUwYYAFACpKINAGcAXJhQwAlFAC0APigA5MCmKSAdDsbNyVOhy49%2BQkRKiiYIOUtXrNUHVvrHYxa3wAekmAFcEMmIAbVQYABopGABdKAAfWEDgkOsQKLSYu2U1DXFaKELuXkFvGVogA)

```python
from typing import overload

@overload
def foo(*args: int) -> None: ...
@overload
def foo(*args: str) -> None: ...

def test(x: tuple[int, int] | tuple[str, str]) -> None:
foo(*x)
```

Produces false positive error:

```
Argument of type "int | str" cannot be assigned to parameter "args" of type "str" in function "foo"
Type "int | str" is not assignable to type "str"
"int" is not assignable to "str" (reportArgumentType)
```

Reproduce the example in the linked Pyright playground and confirm the false positive for foo(*x), where x is a union of tuples. Start by tracing overload resolution for expanded tuple arguments and identify how the union is being checked. Done means the example produces no reportArgumentType diagnostic while preserving checking for invalid calls.

Written by the indexing model from the issue text.