added stt_en_conformer_transducer_large_ls to NGC
Signed-off-by: Vahid <vnoroozi@nvidia.com>

# What does this PR do ?

Added stt_en_conformer_transducer_large_ls  to NGC. A Conformer-Transducer-Large just trained on LS.

**Collection**: ASR

# Changelog 
- Added a new model stt_en_conformer_transducer_large_ls to NGC (A Conformer-Transducer-Large just trained on LS)

**PR Type**:
- [x ] New Feature
- [ ] Bugfix
- [ ] Documentation
