Common Voice datasets still need `use_auth_token=True`

### Describe the bug

We don't need to pass `use_auth_token=True` anymore to download gated datasets or models, so the following should work if correctly logged in.

```py
from datasets import load_dataset

load_dataset("mozilla-foundation/common_voice_6_1", "tr", split="train+validation")
```

However it throws an error - probably because something weird is hardcoded into the dataset loading script.

### Steps to reproduce the bug

1.) 
```
huggingface-cli login
```

2.) Make sure that you have accepted the license here:
https://huggingface.co/datasets/mozilla-foundation/common_voice_6_1

3.) Run:
```py
from datasets import load_dataset

load_dataset("mozilla-foundation/common_voice_6_1", "tr", split="train+validation")
```

4.)  You'll get:

```
File ~/hf/lib/python3.10/site-packages/datasets/builder.py:963, in DatasetBuilder._download_and_prepare(self, dl_manager, verification_mode, **prepare_split_kwargs)
    961 split_dict = SplitDict(dataset_name=self.name)
    962 split_generators_kwargs = self._make_split_generators_kwargs(prepare_split_kwargs)
--> 963 split_generators = self._split_generators(dl_manager, **split_generators_kwargs)
    965 # Checksums verification
    966 if verification_mode == VerificationMode.ALL_CHECKS and dl_manager.record_checksums:

File ~/.cache/huggingface/modules/datasets_modules/datasets/mozilla-foundation--common_voice_6_1/f4d7854c466f5bd4908988dbd39044ec4fc634d89e0515ab0c51715c0127ffe3/common_voice_6_1.py:150, in CommonVoice._split_generators(self, dl_manager)
    148 hf_auth_token = dl_manager.download_config.use_auth_token
    149 if hf_auth_token is None:
--> 150     raise ConnectionError(
    151         "Please set use_auth_token=True or use_auth_token='<TOKEN>' to download this dataset"
    152     )
    154 bundle_url_template = STATS["bundleURLTemplate"]
    155 bundle_version = bundle_url_template.split("/")[0]

ConnectionError: Please set use_auth_token=True or use_auth_token='<TOKEN>' to download this dataset
```

### Expected behavior

One should not have to pass `use_auth_token=True`. Also see discussion here: https://github.com/huggingface/blog/pull/1243#discussion_r1235131150

### Environment info

```
- `datasets` version: 2.13.0
- Platform: Linux-6.2.0-76060200-generic-x86_64-with-glibc2.35
- Python version: 3.10.6
- Huggingface_hub version: 0.16.0.dev0
- PyArrow version: 11.0.0
- Pandas version: 1.5.3
```

cc @pcuenca as well. 

Not super urgent btw

The issue commes from the dataset itself and is not related to the `datasets` lib

see https://huggingface.co/datasets/mozilla-foundation/common_voice_6_1/blob/2c475b3b88e0f2e5828f830a4b91618a25ff20b7/common_voice_6_1.py#L148-L152

Let's remove these lines in the dataset no? cc @anton-l @Vaibhavs10 

Addressed in:

* `mozilla-foundation/common_voice_1_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_1_0/discussions/4)
* `mozilla-foundation/common_voice_2_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_2_0/discussions/3)
* `mozilla-foundation/common_voice_3_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_3_0/discussions/3)
* `mozilla-foundation/common_voice_4_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_4_0/discussions/3)
* `mozilla-foundation/common_voice_5_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_5_0/discussions/3)
* `mozilla-foundation/common_voice_5_1` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_5_1/discussions/3)
* `mozilla-foundation/common_voice_6_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_6_0/discussions/3)
* `mozilla-foundation/common_voice_6_1` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_6_1/discussions/3)
* `mozilla-foundation/common_voice_7_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_7_0/discussions/3)
* `mozilla-foundation/common_voice_8_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_8_0/discussions/7)
* `mozilla-foundation/common_voice_9_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_9_0/discussions/8)
* `mozilla-foundation/common_voice_10_0` [PR](https://huggingface.co/datasets/mozilla-foundation/common_voice_10_0/discussions/7)