Incorrect `redundant-expr` error for `isinstance` on constrained `TypeVar`s

### Describe the problem, ie expected/actual result (if it's not blatantly obvious)

```py
def f[T: (int, str)](t: T):
    if isinstance(t, int):  # always true and always false
        ...
```

### Gist to reproduce

https://mypy-play.net/?mypy=basedmypy-latest&python=3.12&gist=fd75669322cbcbe6bb7c20b985768813


### Basedmypy version

basedmypy 2.5.0 (compiled: yes)
