Adding a decorator to a dataclass breaks the signature

**Describe the bug**
Adding a decorator on top of `@dataclasses.dataclass` messes up the class's call signature.

**Code or Screenshots**

```python
import dataclasses
import typing as t

def some_decorator[**P, R](func: t.Callable[P, R]) -> t.Callable[P, R]:
return func

@some_decorator
@dataclasses.dataclass
class MyClass:
foo: str

MyClass('hello') # Error: Expected 0 positional arguments
```

Start with the supplied Python reproducer and trace how Pyright analyzes a dataclass wrapped by a generic decorator. Look for the existing handling of synthesized dataclass call signatures and verify the behavior with MyClass('hello'). Done means the example no longer reports an incorrect zero-argument signature.

Written by the indexing model from the issue text.