Error in loading the Arabic Billion Words Corpus
Thanks @M-Salti for reporting this issue and for your investigation.

Indeed, those `IndexError` should be catched and the corresponding record should be ignored.

I'm opening a Pull Request to fix it.
## Describe the bug
I get `IndexError: list index out of range` when trying to load the `Techreen` and `Almustaqbal` configs of the dataset.

## Steps to reproduce the bug
```python
load_dataset("arabic_billion_words", "Techreen")
load_dataset("arabic_billion_words", "Almustaqbal")
```

## Expected results
The datasets load succefully.

## Actual results
```python
_extract_tags(self, sample, tag)
    139             if len(out) > 0:
    140                 break
--> 141         return out[0]
    142 
    143     def _clean_text(self, text):

IndexError: list index out of range
```

## Environment info
<!-- You can run the command `datasets-cli env` and copy-and-paste its output below. -->
- `datasets` version: 1.10.2
- Platform: Ubuntu 18.04.5 LTS
- Python version: 3.7.11
- PyArrow version: 3.0.0

Error in loading the Arabic Billion Words Corpus 
 ## Describe the bug
I get `IndexError: list index out of range` when trying to load the `Techreen` and `Almustaqbal` configs of the dataset.

## Steps to reproduce the bug
```python
load_dataset("arabic_billion_words", "Techreen")
load_dataset("arabic_billion_words", "Almustaqbal")
```

## Expected results
The datasets load succefully.

## Actual results
```python
_extract_tags(self, sample, tag)
    139             if len(out) > 0:
    140                 break
--> 141         return out[0]
    142 
    143     def _clean_text(self, text):

IndexError: list index out of range
```

## Environment info
<!-- You can run the command `datasets-cli env` and copy-and-paste its output below. -->
- `datasets` version: 1.10.2
- Platform: Ubuntu 18.04.5 LTS
- Python version: 3.7.11
- PyArrow version: 3.0.0
 
 Thanks @M-Salti for reporting this issue and for your investigation.

Indeed, those `IndexError` should be catched and the corresponding record should be ignored.

I'm opening a Pull Request to fix it.