Debug Transformer Engine FP8 support with Megatron-core infrastructure
# What does this PR do ?

Debugs Transformer Engine FP8 support with Megatron-core infrastructure

**Collection**: NLP

# Changelog
- Construct FP8 amax reduction group 

# Usage

Set `transformer_engine: True` and `fp8: True` in the config.

# 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?
- [ ] 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
- [ ] Documentation

If you haven't finished some of the above items you can still open "Draft" PR.


## 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.

Pinging @aklife97 @yen-shi @erhoo82 @ksivaman 

# Additional Information
* Requires https://github.com/NVIDIA/Megatron-LM/commit/f267e6186eae1d6e2055b412b00e2e545a8e896a
* Fixes bug from https://github.com/NVIDIA/NeMo/pull/6393
* Subset of https://github.com/NVIDIA/NeMo/pull/6627
* Closes https://github.com/NVIDIA/NeMo/issues/6625