Update TitaNet-L and MSDD models 
# What does this PR do ?

* Update hydra config on published NGC titanet-model and release as v1 version
* Improve speaker label tests with latest hydra config
* Add a feature to write model labels `labels.txt` to exp directory 
* Update batch inference function to return gt labels and trained model labels (if available) 

**Collection**: ASR

# Changelog 
- Update label models to include latest v1 version of titanet-large
- Added titanet-small config file (model will be published soon)
- Now instead of returning index of gt labels from AudioSpeechLabelDataset, return the speaker label names directly as seen from manifest file

# Before your PR is "Ready for review"
**Pre checks**:
- [ ] Make sure you read and followed [Contributor guidelines](https://github.com/NVIDIA/NeMo/blob/main/CONTRIBUTING.md)
- [ ] Did you write any new necessary tests?
- [ ] Did you add or update any necessary documentation?
- [ ] Does the PR affect components that are optional to install? (Ex: Numba, Pynini, Apex etc)
  - [ ] Reviewer: Does the PR have correct import guards for all optional libraries?
  
**PR Type**:
- [ ] New Feature
- [x] Bugfix
- [x] Documentation 