Duplicate import statement for `google.longrunning.operations_pb2` in `python-logging`

In PR https://github.com/googleapis/python-logging/pull/746, there is a duplicate import statement for `google.longrunning.operations_pb2`. See the review comment [here](https://github.com/googleapis/python-logging/pull/746#discussion_r1190481195).