Fix FSDP no longer working

[muellerzr]

What does this PR do?

#34140 introduced a breaking change that users are reporting has many downstream issues:

• KeyError: Parameter containing peft#2205
• Error During Model Saving QLORA + FSDP axolotl-ai-cloud/axolotl#2149

This PR reverts the breaking logic, while also maintaining the original test the user intended, in such a way that doesn't break downstream code. I'd highly recommend a patch with this fix @ArthurZucker

Fixes huggingface/peft#2205
Fixes axolotl-ai-cloud/axolotl#2149

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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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
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@ArthurZucker @winglian @SunMarc @BenjaminBossan

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[SunMarc]

LGTM !

[BenjaminBossan]

Testing this change locally, I can confirm that it enables my testing example to run successfully. There is an exception, namely when flash attention is being used, for some reason (perhaps it's an issue with my setup). But even so, this is an improvement and can be merged from my point of view.

[ArthurZucker]

Failures are unrelated!