Override Transformers defaults by GGUF defaults
Author: a4lg
Pull request: yes

# What does this PR do?

In some models, GGUF uses default or fixed values different from this library.
To integrate GGUF-based models without additional configuration (and/or individual `config.json`), we need some kind of compatibility layer (like tensor processors in `src/transformers/modeling_gguf_pytorch_utils.py` while loading/converting GGUF-based model tensors).

This commit provides additional mapping to provide GGUF-specific default values to initialize parameters in this library.

Currently, only fixed `norm_topk_prob` value of Qwen3 MoE (`True`) is defined because:

1.  It differs from the default value of this library (`False`) and
2.  If this parameter is incorrectly set, it results in almost completely garbled output (see vllm-project/vllm#30118 for examples).

I'm sure that Qwen3 MoE + GGUF issue should be addressed somehow but I'm not sure whether this PR is the right way to fix the issue.
So, feel free to leave a review!

I could not check all parameters but at least I checked important parameters for MoE models with GGUF support in this library.

## Before submitting
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- [ ] Did you write any new necessary tests?


## Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

@CyrilVallez @SunMarc @MekkCyber

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