no error when `Final` value reassigned in loop

### Summary

```py
from typing import Final

ABC: Final

for i in range(2):
    ABC = i  # expect error
```


but i hope that declaring a final variable in a loop is not removed:
```py
for i in range(10):
  i_str: Final = str(i)  # i like that this is allowed, please don't remove it
```