Added deprecation notice
[🤖]: Hi @Ssofja 👋,

We wanted to let you know that a [CICD pipeline](https://github.com/NVIDIA/NeMo/actions/runs/11666093312) for this PR just finished successfully

So it might be time to merge this PR or get some approvals

I'm just a bot so I'll leave it you what to do next.

//cc @pablo-garay @ko3n1g
# What does this PR do ?
Some deprecation notices have added for future code refactoring 
Add a one line overview of what this PR aims to accomplish.

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

## Who can review?

Anyone in the community is free to review the PR once the checks have passed. 
[Contributor guidelines](https://github.com/NVIDIA/NeMo/blob/main/CONTRIBUTING.md) contains specific people who can review PRs to various areas.