Dataset viewer for nli_tr
It's an issue with the streaming mode:

```python
>>> import datasets
>>> dataset = datasets.load_dataset('nli_tr', name='snli_tr',split='test', streaming=True)
>>> next(iter(dataset))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/slesage/hf/datasets-preview-backend/.venv/lib/python3.9/site-packages/datasets/iterable_dataset.py", line 497, in __iter__
    for key, example in self._iter():
  File "/home/slesage/hf/datasets-preview-backend/.venv/lib/python3.9/site-packages/datasets/iterable_dataset.py", line 494, in _iter
    yield from ex_iterable
  File "/home/slesage/hf/datasets-preview-backend/.venv/lib/python3.9/site-packages/datasets/iterable_dataset.py", line 87, in __iter__
    yield from self.generate_examples_fn(**self.kwargs)
  File "/home/slesage/.cache/huggingface/modules/datasets_modules/datasets/nli_tr/c2ddd0c0a70caddac6a81c2dae5ca7939f00060d517d08f1983927818dba6521/nli_tr.py", line 155, in _generate_examples
    with codecs.open(filepath, encoding="utf-8") as f:
  File "/home/slesage/.pyenv/versions/3.9.6/lib/python3.9/codecs.py", line 905, in open
    file = builtins.open(filename, mode, buffering)
FileNotFoundError: [Errno 2] No such file or directory: 'zip://snli_tr_1.0_test.jsonl::https://tabilab.cmpe.boun.edu.tr/datasets/nli_datasets/snli_tr_1.0.zip'
```

Note that normal mode is used by the dataset viewer when streaming is failing, but only for the smallest datasets. `nli_tr` is above the limit, hence the error. cc @huggingface/datasets  Apparently there is an issue with the data source URLs: Server Not Found
- https://tabilab.cmpe.boun.edu.tr/datasets/nli_datasets/snli_tr_1.0.zip

We are contacting the authors to ask them: 
@e-budur you are one of the authors: are you aware of the issue with the URLs of your data ? Reported to their repo:
- https://github.com/boun-tabi/NLI-TR/issues/9 The server issue was temporary and is now resolved. Once we have implemented support for streaming, the viewer works: https://huggingface.co/datasets/nli_tr
## Dataset viewer issue for '*nli_tr*'

**Link:** https://huggingface.co/datasets/nli_tr

Hello,

Thank you for the new dataset preview feature that will help the users to view the datasets online.

We just noticed that the dataset viewer widget in the `nli_tr` dataset shows the error below. The error must be due to a temporary problem that may have blocked access to the dataset through the dataset viewer. But the dataset is currently accessible through the link in the error message.   May we kindly ask if it would be possible to rerun the job so that it can access the dataset for the dataset viewer function?

Thank you.
Emrah


------------------------------------------
Server Error
Status code:   404
Exception:     FileNotFoundError
Message:       [Errno 2] No such file or directory: 'zip://snli_tr_1.0_train.jsonl::https://tabilab.cmpe.boun.edu.tr/datasets/nli_datasets/snli_tr_1.0.zip
------------------------------------------

Am I the one who added this dataset ? Yes
