Fix crash when converting to mcore a model using rotary embeddings
jenkins jenkins
# What does this PR do ?

Fix crash when converting to mcore a model using rotary embeddings.

The problem is that mcore models don't register `rotary_pos_emb.inv_freq` as a buffer anymore.

I made it a command-line argument so that if the same issue occurs with other parameters / buffers, users can still run the conversion script by providing them on the command-line (instead of having to wait for a new version of NeMo).

I tested this PR on a model where the script failed previously with container `nemofw-training:23.11`.

**Collection**: nlp

# Changelog 
- Fix crash when converting to mcore a model using rotary embeddings

# 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


## 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.