num_samples is zero, but 1172 files were filtered
**Describe the bug**

I am getting this error when I try to instantiate ASR model (following [this](https://github.com/NVIDIA/NeMo/blob/v1.0.0/tutorials/asr/01_ASR_with_NeMo.ipynb) tutorial):

`ValueError: num_samples should be a positive integer value, but got num_samples=0`

But it's quite strange because I am getting these logs during the run:

```
[NeMo I 2022-01-21 11:37:29 audio_to_text_dataset:38] Model level config does not container `sample_rate`, please explicitly provide `sample_rate` to the dataloaders.

[NeMo I 2022-01-21 11:37:29 audio_to_text_dataset:38] Model level config does not container `labels`, please explicitly provide `labels` to the dataloaders.

[NeMo I 2022-01-21 11:37:29 collections:173] Dataset loaded with 0 files totalling 0.00 hours

[NeMo I 2022-01-21 11:37:29 collections:174] 1172 files were filtered totalling 347.43 hours
```

Which shows correct number of files (`1172`) in training dataset.

**Steps/Code to reproduce bug**

```python
trainer = pl.Trainer(gpus=1, max_epochs=50)

train_manifest = './<folder_name>/manifests/train_manifest.json'
test_manifest = './<folder_name>/manifests/test_manifest.json'

params['model']['train_ds']['manifest_filepath'] = train_manifest
params['model']['validation_ds']['manifest_filepath'] = test_manifest

first_asr_model = nemo_asr.models.EncDecCTCModel(cfg=DictConfig(params['model']), trainer=trainer)
```

I have tried to put full path for `train_manifest` and `test_manifest` (`/home/ubuntu/<folder_name>/manifests`), but it didn't help at all.

**Expected behavior**

Running without errors.

**Environment overview (please complete the following information)**

 - Environment location: `Jupyter Notebook` in `AWS EC2` instance node
 - Method of NeMo install: `pip install nemo_toolkit[all]`

**Environment details**

If NVIDIA docker image is used you don't need to specify these.
Otherwise, please provide:
- OS version: Ubuntu 20.04.3 LTS
- PyTorch version: 1.10.1
- Python version: 3.8.12

**Additional context**
It doesn't seem that there are no files or the path to the `train` and `test` manifests are incorrect. Otherwise I couldn't open manifests via `pandas` (did this for checking purposes). The structure of the manifest looks like this:

`
{"audio_filepath": "/home/ubuntu/<folder_name>/audio/<audio_file_name>.wav", "duration": 1725.84, "text": "..."}
{"audio_filepath": "/home/ubuntu/<folder_name>/audio/<audio_file_name>.wav", "duration": 1725.84, "text": "..."}
`

where `<folder_name>` is the same as in the path for `train_manifest.json` and `test_manifest.json`.