Datasets crashing runs due to KeyError

### Describe the bug

Hi all,

I have been running into a pretty persistent issue recently when trying to load datasets. 
```python
    train_dataset = load_dataset(
        'llama-2-7b-tokenized', 
        split = 'train'
    )
```
I receive a KeyError which crashes the runs.
```
Traceback (most recent call last):
    main()

    train_dataset = load_dataset(
                    ^^^^^^^^^^^^^
    builder_instance = load_dataset_builder(
                       ^^^^^^^^^^^^^^^^^^^^^
    dataset_module = dataset_module_factory(
                     ^^^^^^^^^^^^^^^^^^^^^^^
    raise e1 from None

    ).get_module()
      ^^^^^^^^^^^^
    else get_data_patterns(base_path, download_config=self.download_config)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    return _get_data_files_patterns(resolver)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    data_files = pattern_resolver(pattern)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^
    fs, _, _ = get_fs_token_paths(pattern, storage_options=storage_options)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    paths = [f for f in sorted(fs.glob(paths)) if not fs.isdir(f)]
                               ^^^^^^^^^^^^^^

    allpaths = self.find(root, maxdepth=depth, withdirs=True, detail=True, **kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    for _, dirs, files in self.walk(path, maxdepth, detail=True, **kwargs):

    listing = self.ls(path, detail=True, **kwargs)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    "last_modified": parse_datetime(tree_item["lastCommit"]["date"]),
                                    ~~~~~~~~~^^^^^^^^^^^^^^
KeyError: 'lastCommit'
```
Any help would be greatly appreciated.

Thank you,

Enrico

### Steps to reproduce the bug

Load the dataset from the Huggingface hub.
```python
    train_dataset = load_dataset(
        'llama-2-7b-tokenized', 
        split = 'train'
    )
```

### Expected behavior

Loads the dataset.

### Environment info

datasets-2.14.3
CUDA 11.8
Python 3.11

i once had the same error and I could fix that by pushing a fake or a dummy commit on my hugging face dataset repo

Hi! We need a reproducer to fix this. Can you provide a link to the dataset (if it's public)?

> Hi! We need a reproducer to fix this. Can you provide a link to the dataset (if it's public)?

Hi Mario,

Unfortunately, the dataset in question is currently private until the model is trained and released.

This is not happening with one dataset but numerous hosted private datasets.

I am only loading the dataset and doing nothing else currently. It seems to happen completely sporadically.

Thank you,

Enrico

Hi,

I have the same error in the dataset viewer with my dataset
https://huggingface.co/datasets/elsaEU/ELSA10M_track1

Has anyone solved this issue?

Edit: After a dummy commit the error changed in ConfigNamesError

@rs9000 The problem seems to be the (large) number of commits, as explained in https://huggingface.co/docs/hub/repositories-recommendations. This can be fixed by running:
```python
import huggingface_hub
huggingface_hub.super_squash_history(repo_id="elsaEU/ELSA10M_track1")
``` 

The issue stems from `push_to_hub` creating one commit per shard -  https://github.com/huggingface/datasets/pull/6269 should fix this issue (will create one commit per 50 uploaded shards by default). The linked PR will be included in the next `datasets` release.


cc @lhoestq @severo for visibility

Thank you @mariosasko it works.

#6269 has been merged, so I'm closing this issue