Issue: Loading mozilla-foundation/common_voice_7_0 dataset failed

## Describe the bug
I wanted to load `mozilla-foundation/common_voice_7_0` dataset with `fi` language and `test` split from datasets on Colab/Kaggle notebook, but I am getting an error `JSONDecodeError: [Errno Expecting value] Not Found: 0` while loading it. The bug seems to affect other languages and splits too than just the `fi` and `test` split.

## Steps to reproduce the bug
```python
from datasets import load_dataset
dataset = load_dataset("mozilla-foundation/common_voice_7_0", "fi", split="test", use_auth_token="YOUR TOKEN")
```

## Expected results
load `mozilla-foundation/common_voice_7_0` dataset succesfully

## Actual results
```
JSONDecodeError                           Traceback (most recent call last)
/opt/conda/lib/python3.7/site-packages/requests/models.py in json(self, **kwargs)
    909         try:
--> 910             return complexjson.loads(self.text, **kwargs)
    911         except JSONDecodeError as e:

/opt/conda/lib/python3.7/site-packages/simplejson/__init__.py in loads(s, encoding, cls, object_hook, parse_float, parse_int, parse_constant, object_pairs_hook, use_decimal, **kw)
    524             and not use_decimal and not kw):
--> 525         return _default_decoder.decode(s)
    526     if cls is None:

/opt/conda/lib/python3.7/site-packages/simplejson/decoder.py in decode(self, s, _w, _PY3)
    369             s = str(s, self.encoding)
--> 370         obj, end = self.raw_decode(s)
    371         end = _w(s, end).end()

/opt/conda/lib/python3.7/site-packages/simplejson/decoder.py in raw_decode(self, s, idx, _w, _PY3)
    399                 idx += 3
--> 400         return self.scan_once(s, idx=_w(s, idx).end())

JSONDecodeError: Expecting value: line 1 column 1 (char 0)

During handling of the above exception, another exception occurred:

JSONDecodeError                           Traceback (most recent call last)
/tmp/ipykernel_358/370980805.py in <module>
      1 # load Common Voice 7.0 dataset from Huggingface with Finnish "test" split
----> 2 test_dataset = load_dataset("mozilla-foundation/common_voice_7_0", "fi", split="test", use_auth_token=True)

/opt/conda/lib/python3.7/site-packages/datasets/load.py in load_dataset(path, name, data_dir, data_files, split, cache_dir, features, download_config, download_mode, ignore_verifications, keep_in_memory, save_infos, revision, use_auth_token, task, streaming, **config_kwargs)
   1690         ignore_verifications=ignore_verifications,
   1691         try_from_hf_gcs=try_from_hf_gcs,
-> 1692         use_auth_token=use_auth_token,
   1693     )
   1694 

/opt/conda/lib/python3.7/site-packages/datasets/builder.py in download_and_prepare(self, download_config, download_mode, ignore_verifications, try_from_hf_gcs, dl_manager, base_path, use_auth_token, **download_and_prepare_kwargs)
    604                     if not downloaded_from_gcs:
    605                         self._download_and_prepare(
--> 606                             dl_manager=dl_manager, verify_infos=verify_infos, **download_and_prepare_kwargs
    607                         )
    608                     # Sync info

/opt/conda/lib/python3.7/site-packages/datasets/builder.py in _download_and_prepare(self, dl_manager, verify_infos)
   1102 
   1103     def _download_and_prepare(self, dl_manager, verify_infos):
-> 1104         super()._download_and_prepare(dl_manager, verify_infos, check_duplicate_keys=verify_infos)
   1105 
   1106     def _get_examples_iterable_for_split(self, split_generator: SplitGenerator) -> ExamplesIterable:

/opt/conda/lib/python3.7/site-packages/datasets/builder.py in _download_and_prepare(self, dl_manager, verify_infos, **prepare_split_kwargs)
    670         split_dict = SplitDict(dataset_name=self.name)
    671         split_generators_kwargs = self._make_split_generators_kwargs(prepare_split_kwargs)
--> 672         split_generators = self._split_generators(dl_manager, **split_generators_kwargs)
    673 
    674         # Checksums verification

~/.cache/huggingface/modules/datasets_modules/datasets/mozilla-foundation--common_voice_7_0/fe20cac47c166e25b1f096ab661832e3da7cf298ed4a91dcaa1343ad972d175b/common_voice_7_0.py in _split_generators(self, dl_manager)
    151 
    152         self._log_download(self.config.name, bundle_version, hf_auth_token)
--> 153         archive = dl_manager.download(self._get_bundle_url(self.config.name, bundle_url_template))
    154 
    155         if self.config.version < datasets.Version("5.0.0"):

~/.cache/huggingface/modules/datasets_modules/datasets/mozilla-foundation--common_voice_7_0/fe20cac47c166e25b1f096ab661832e3da7cf298ed4a91dcaa1343ad972d175b/common_voice_7_0.py in _get_bundle_url(self, locale, url_template)
    130         path = urllib.parse.quote(path.encode("utf-8"), safe="~()*!.'")
    131         use_cdn = self.config.size_bytes < 20 * 1024 * 1024 * 1024
--> 132         response = requests.get(f"{_API_URL}/bucket/dataset/{path}/{use_cdn}", timeout=10.0).json()
    133         return response["url"]
    134 

/opt/conda/lib/python3.7/site-packages/requests/models.py in json(self, **kwargs)
    915                 raise RequestsJSONDecodeError(e.message)
    916             else:
--> 917                 raise RequestsJSONDecodeError(e.msg, e.doc, e.pos)
    918 
    919     @property

JSONDecodeError: [Errno Expecting value] Not Found: 0
```

## Environment info
- `datasets` version: 2.0.0
- Platform: Linux-5.10.90+-x86_64-with-debian-bullseye-sid
- Python version: 3.7.12
- PyArrow version: 5.0.0
- Pandas version: 1.3.5


Comments:
Hi @aapot, thanks for reporting.

We are investigating the cause of this issue. We will keep you informed. 

When making HTTP request from code line:
```
response = requests.get(f"{_API_URL}/bucket/dataset/{path}/{use_cdn}", timeout=10.0).json()
```
it cannot be decoded to JSON because it raises a 404 Not Found error.

The request is fixed if removing the `/{use_cdn}` from the URL.

Maybe there was a change in the Common Voice API?

CC: @anton-l @patrickvonplaten @polinaeterna 

We have contacted by email the data owners of the Common Voice dataset.

Hotfix: https://huggingface.co/datasets/mozilla-foundation/common_voice_7_0/commit/17b237961e4f7f84a2a0aea645abe5428a9d568e

I have also made the hotfix for all the rest of Common Voice script versions: 8.0, 6.1, 6.0,..., 1.0

Hey, is there anything new?
I could not load the dataset.

cc @lhoestq @polinaeterna 

Hi @ngoquanghuy99! The dataset should load fine if you go through the following steps:

1. Go to https://huggingface.co/datasets/mozilla-foundation/common_voice_9_0 and click "Access repository" if you see a message about sharing your contact information with Mozilla Foundation at the top of the page. If you've already done that then skip to step 2.
2. Run the command `huggingface-cli login` in your terminal or notebook to authenticate your machine.
3. Load the dataset with `use_auth_token=True`:
```python
from datasets import load_dataset

dataset = load_dataset("mozilla-foundation/common_voice_9_0", "ab", use_auth_token=True)
```

Thanks @anton-l 
I could load the dataset now, but in another way.
Thanks anyways!

> Thanks @anton-l I could load the dataset now, but in another way. Thanks anyways!

Can you share the "another way" please?