Check override consistency w/ superclass's `__getattr__`

### Describe the Bug

```py
class A:
known: str
def __getattr__(self, attr: str) -> int:
return 1
class B(A):
also_known: str

def f(a: A = B()):
a.also_known # pyrefly: int, runtime: str
```

an error should be shown on the declaration of `also_known`

### Sandbox Link

_No response_

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

_No response_