add fc large ls models
# What does this PR do ?

Add fc large LS only trained models to pretrained list and docs

**Collection**: ASR

# Changelog 
- Add to pretrained list

# Usage

```python
from nemo.collections.asr.models import ASRModel
model = ASRModel.from_pretrained('stt_en_fastconformer_transducer_large_ls')
# or
model = ASRModel.from_pretrained('stt_en_fastconformer_ctc_large_ls')
```

# Before your PR is "Ready for review"
**Pre checks**:
- [x] Make sure you read and followed [Contributor guidelines](https://github.com/NVIDIA/NeMo/blob/main/CONTRIBUTING.md)
- [ ] Did you write any new necessary tests?
- [x] 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
- [ ] Bugfix
- [x] Documentation