File not found error while loading titanet_small
Hello,

I am trying to load titanet small using the following line of code: 
```
nemo_speaker_model_small = EncDecSpeakerLabelModel.from_pretrained(model_name="titanet_small")
```

Here is the error:
```FileNotFoundError: Model titanet_small was not found. Check cls.list_available_models() for the list of all available models.```

I am using the latest nemo_toolkit
