fix:(bindings/python) changes required in `dev/src/generate/python.j2`

@Xuanwo aren't some changes required in `dev/src/generate/python.j2` as well. otherwise these will be overwritten by `just generate python`

_Originally posted by @chitralverma in https://github.com/apache/opendal/pull/6668#discussion_r2436556206_
            