Add traceable mistral and mistral3 classes

[anmarques]

SUMMARY:
This PR adds traceable versions of Mistral and Mistral3.

NOTE:
The code fails quality and style tests, but I think we should ignore them. The failures occur at the model definitions ported from transformers and keeping the changes to a minimal would help to maintain these. I added ignore commands to the headers to automatically skip linting.

TEST PLAN:

llmcompressor.trace \
    --model_id "mistralai/Mistral-Small-3.1-24B-Instruct-2503" \
    --model_class "TraceableMistral3ForConditionalGeneration" \
    --sequential_targets "MistralDecoderLayer" \
    --ignore "language_model.lm_head" "re:vision_tower.*" "re:multi_modal_projector.*" \
    --modality vision

llmcompressor.trace \
    --model_id "mistralai/Mistral-Small-3.1-24B-Instruct-2503" \
    --model_class "TraceableMistral3ForConditionalGeneration" \
    --sequential_targets "MistralDecoderLayer" \
    --ignore "language_model.lm_head" "re:vision_tower.*" "re:multi_modal_projector.*" \
    --modality text

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[dsikka]

I think if we want to ignore linting/style, we should add lines to skip linting:
e.g:

llm-compressor/src/llmcompressor/__init__.py

Line 9 in 352579b

# flake8: noqa

[anmarques]

I think if we want to ignore linting/style, we should add lines to skip linting: e.g:

llm-compressor/src/llmcompressor/__init__.py

Line 9 in 352579b

# flake8: noqa

I wasn't aware this is an option. Done. Thanks

[anmarques]

Converted to draft because things are still in flux until we upgrade transformers support

[kylesayrs]

A traceable definition for this model is no longer required as of #1411 having been implemented. The accompanying example and test for this model is implemented here: #1490