new rule - non-decorator usage of `final`

not sure how common this is, but [ty has a check for it](https://docs.astral.sh/ty/reference/rules/#ineffective-final):

```py
from typing import final

# error: Type checkers will not prevent subclassing when `final()` is called as a function
MyClass = final(type("MyClass", (), {}))

class Bar(MyClass): ... # no error
```