HTTPError 403 raised by CLI convert_to_parquet when creating script branch on 3rd party repos
CLI convert_to_parquet cannot create "script" branch on 3rd party repos.

It can only create it on repos where the user executing the script has write access.

Otherwise, a 403 Forbidden HTTPError is raised:
```
Traceback (most recent call last):
  File "/usr/local/lib/python3.10/dist-packages/huggingface_hub/utils/_errors.py", line 304, in hf_raise_for_status
    response.raise_for_status()
  File "/usr/local/lib/python3.10/dist-packages/requests/models.py", line 1021, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 403 Client Error: Forbidden for url: https://huggingface.co/api/datasets/ORG/DATASET/branch/script

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/local/bin/datasets-cli", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.10/dist-packages/datasets/commands/datasets_cli.py", line 41, in main
    service.run()
  File "/usr/local/lib/python3.10/dist-packages/datasets/commands/convert_to_parquet.py", line 92, in run
    create_branch(dataset_id, branch="script", repo_type="dataset", token=token, exist_ok=True)
  File "/usr/local/lib/python3.10/dist-packages/huggingface_hub/utils/_validators.py", line 114, in _inner_fn
    return fn(*args, **kwargs)
  File "/usr/local/lib/python3.10/dist-packages/huggingface_hub/hf_api.py", line 5503, in create_branch
    hf_raise_for_status(response)
  File "/usr/local/lib/python3.10/dist-packages/huggingface_hub/utils/_errors.py", line 367, in hf_raise_for_status
    raise HfHubHTTPError(message, response=response) from e
huggingface_hub.utils._errors.HfHubHTTPError:  (Request ID: Root=1-6645ee0d-4db1ed8a1fbe04956be15897;139a6e23-df7d-4f62-b5ba-adb6d8e6e696)

403 Forbidden: Forbidden: cannot write to script.
Cannot access content at: https://huggingface.co/api/datasets/ORG/DATASET/branch/script.
If you are trying to create or update content,make sure you have a token with the `write` role.
```