Trying to access splits inside the ds-info, which is an empty dict

/!\ PLEASE INCLUDE THE FULL STACKTRACE AND CODE SNIPPET

Short description
Description of the bug.

The Splits dictionary coming as empty when you use the latest version of the tensorflow-datasets =4.8.3 ,but if you use the tensorflow-datasets=4.8.2 version, its working fine.

Environment information

• Operating System:

• Python version:

• tensorflow-datasets/tfds-nightly version:

• tensorflow/tf-nightly version:

• Does the issue still exists with the last tfds-nightly package (pip install --upgrade tfds-nightly) ?

Reproduction instructions

Use the latest version of the `pip install tensorflow-datasets =4.8.3' ,you will see the error.

tfds_name = 'cifar10'
ds_info = tfds.builder(tfds_name ).info
ds_info.splits['test'].num_examples

Link to logs

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
[<ipython-input-6-08c8a6b834e3>](https://localhost:8080/#) in <module>
     21 exp_config.trainer.checkpoint_interval = train_steps
     22 exp_config.trainer.validation_interval = 1000
---> 23 exp_config.trainer.validation_steps =  ds_info.splits['test'].num_examples // batch_size
     24 exp_config.trainer.train_steps = train_steps
     25 exp_config.trainer.optimizer_config.learning_rate.type = 'cosine'

[/usr/local/lib/python3.8/dist-packages/tensorflow_datasets/core/splits.py](https://localhost:8080/#) in __getitem__(self, key)
    389   def __getitem__(self, key):
    390     if not self:
--> 391       raise KeyError(
    392           f'Trying to access `splits[{key!r}]` but `splits` is empty. '
    393           'This likely indicate the dataset has not been generated yet.'

KeyError: "Trying to access `splits['test']` but `splits` is empty. This likely indicate the dataset has not been generated yet."

Expected behavior
The Splits dictionary should not come as empty

Additional context