fix os.listdir return name is empty string
### Describe the bug

xlistdir return name is empty string 
Overloaded os.listdir

### Steps to reproduce the bug

```python
from datasets.download.streaming_download_manager import xjoin
from datasets.download.streaming_download_manager import xlistdir
config = DownloadConfig(storage_options=options)
manger = StreamingDownloadManager("ILSVRC2012",download_config=config)
input_path = "lakefs://datalab/main/imagenet/ILSVRC2012.zip"

download_files = manger.download_and_extract(input_path)

current_dir = xjoin(download_files,"ILSVRC2012/Images/ILSVRC2012_img_train")
folder_list = xlistdir(current_dir)
```

in xlistdir function

Obj ["name"] ends with "/"

last return ""

### Expected behavior

Obj ["name"] ends with "/" 
return folder name

### Environment info

no