fix: switch torch_dynamic and quanto saves to save_before_apply

[gsprochette]

Description

In transformers 5, llama architectures are not picklable because of the choice of kernel functions.
Both quanto and torch_dynamic were facing saving problems, and are switched to save_before_apply to preserve compatibility with (among other) compilation algorithms (compilation algorithms use save_before_apply -> the quantized model's save functions is called -> for quanto or torch_dynamic that would be torch.save -> error).

Related Issue

Fixes #(issue number)

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactor (no functional change)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Testing

• I added or updated tests covering my changes
• Existing tests pass locally (uv run pytest -m "cpu and not slow")

For full setup and testing instructions, see the Contributing Guide.

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code, especially for agent-assisted changes
• I updated the documentation where necessary

---

Thanks for contributing to Pruna! We're excited to review your work.

New to contributing? Check out our Contributing Guide for everything you need to get started.

Note:

• Draft PRs or PRs without a clear and detailed overview may be delayed.
• Please mark your PR as Ready for Review and ensure the sections above are filled out.
• Contributions that are entirely AI-generated without meaningful human review are discouraged.

[begumcig]

Thank you!!! looks super good to me! :)