speech_to_text generates an error related to the json file?
When I run the following scirpt: https://github.com/NVIDIA/NeMo/blob/main/examples/asr/speech_to_text.py
I get the following error:
```
[NeMo W 2021-09-01 16:08:13 experimental:27] Module <class 'nemo.collections.asr.data.audio_to_text_dali.AudioToCharDALIDataset'> is experimental, not ready for production and is not fully supported. Use at your own risk.
[NeMo I 2021-09-01 16:08:13 speech2text:44] Namespace(config_name='SpeakerNet_verification_3x2x512', config_path='/home/ubuntu/repos/algo/app/aliSrc/notebooks/conf', data_dir='/home/ubuntu/repos/algo/app/aliSrc/dataset/himia/train', gpu=0, max_epochs=50)
[NeMo I 2021-09-01 16:08:13 speech2text:61] =====[NeMo W 2021-09-01 16:08:13 nemo_logging:349] /home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/pytorch_lightning/trainer/connectors/accelerator_connector.py:556: UserWarning: You requested distributed training on GPUs, but none is available, so we set backend to `ddp_cpu`.      rank_zero_warn(

[NeMo W 2021-09-01 16:08:13 nemo_logging:349] /home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/pytorch_lightning/trainer/connectors/accelerator_connector.py:563: UserWarning: You are running on single node with no parallelization, so distributed has no effect.
      rank_zero_warn('You are running on single node with no parallelization, so distributed has no effect.')
GPU available: True, used: False
TPU available: False, using: 0 TPU cores[NeMo W 2021-09-01 16:08:14 nemo_logging:349] /home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/pytorch_lightning/trainer/connectors/accelerator_connector.py:596: UserWarning: GPU available but not used. Set the gpus flag in your trainer `Trainer(gpus=1)` or script `--gpus=1`.      rank_zero_warn(

[NeMo I 2021-09-01 16:08:14 exp_manager:217] Experiments will be logged at /home/ubuntu/repos/algo/app/nemo_experiments/SpeakerNet/2021-09-01_16-08-14[NeMo I 2021-09-01 16:08:14 exp_manager:564] TensorboardLogger has been set up
[NeMo W 2021-09-01 16:08:14 nemo_logging:349] /home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/pytorch_lightning/callbacks/model_checkpoint.py:396: LightningDeprecationWarning: Argument `period` in `ModelCheckpoint` is deprecated in v1.3 and will be removed in v1.5. Please use `every_n_val_epochs` instead.
      rank_zero_deprecation(

[NeMo I 2021-09-01 16:08:14 audio_to_text_dataset:36] Model level config does not container `sample_rate`, please explicitly provide `sample_rate` to the dataloaders.
[NeMo I 2021-09-01 16:08:14 audio_to_text_dataset:36] Model level config does not container `labels`, please explicitly provide `labels` to the dataloaders.
Traceback (most recent call last):
  File "/home/ubuntu/repos/algo/app/aliSrc/src/speech2text.py", line 70, in <module>
    main()
  File "/home/ubuntu/repos/algo/app/aliSrc/src/speech2text.py", line 66, in main
    asr_model = EncDecCTCModel(cfg=cfg.model, trainer=trainer)
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/collections/asr/models/ctc_models.py", line 153, in __init__
    super().__init__(cfg=cfg, trainer=trainer)
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/core/classes/modelPT.py", line 128, in __init__
    self.setup_training_data(self._cfg.train_ds)
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/collections/asr/models/ctc_models.py", line 423, in setup_training_data
    self._train_dl = self._setup_dataloader_from_config(config=train_data_config)
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/collections/asr/models/ctc_models.py", line 390, in _setup_dataloader_from_config
    dataset = audio_to_text_dataset.get_char_dataset(config=config, augmentor=augmentor)
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/collections/asr/data/audio_to_text_dataset.py", line 75, in get_char_dataset
    dataset = audio_to_text.AudioToCharDataset(
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/collections/asr/data/audio_to_text.py",line 250, in __init__
    super().__init__(
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/collections/asr/data/audio_to_text.py",line 139, in __init__
    self.collection = collections.ASRAudioText(
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/collections/common/parts/preprocessing/collections.py", line 193, in __init__
    for item in manifest.item_iter(manifests_files):
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/collections/common/parts/preprocessing/manifest.py", line 72, in item_iter
    item = parse_func(line, manifest_file)
  File "/home/ubuntu/repos/algo/app/aliSrc/aliEnv/lib/python3.8/site-packages/nemo/collections/common/parts/preprocessing/manifest.py", line 107, in __parse_item
    raise ValueError(
ValueError: Manifest file /home/ubuntu/repos/algo/app/aliSrc/dataset/himia/train/train.json has invalid json line structure: {"audio_filepath": "/home/ubuntu/repos/algo/app/aliSrc/dataset/himia/train/SPEECHDATA_reduced/wav/SV0015/SV0015_5_15_N1744.wav", "offset": 0, "duration": 1.5600625, "label": "SV0015"}
 without proper text key.
```

