Download files from subfolders doesn't work

Tried the same code:

```python
from kaggle.api.kaggle_api_extended import KaggleApi

api = KaggleApi()
api.authenticate()

api.competition_download_file(
,
'dataset/dataset_files/filename.ext'
path='local_path'
)
```
Version 1.6.17 downloads file successfully.

Version 1.7.4.2 returns this error:
```
404 Client Error: Not Found for url: https://www.kaggle.com/api/v1/competitions/data/download//dataset/dataset_files/filename.ext
```