[PEFT] Fix peft ci

[younesbelkada]

What does this PR do?

Fixes the current PEFT LoRA CI - we also need: huggingface/transformers#26407 to be merged

With huggingface/peft#905 being merged, the logic for manipulating the active adapter(s) has changed a bit. Now, active_adapter is a property method and returns a list, in order to deal with multiple adapter inference.

This PR adjusts the current PEFT integration by properly dealing with the case module.active_adapter returns a list, therefore fixing the multiple adapter case

cc @BenjaminBossan @pacman100 @patrickvonplaten @sayakpaul

[sayakpaul]

Thank you! Can merge once the CI is green.

[patrickvonplaten]

Merged main into PR to fix flaky test

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint.

[younesbelkada]

Thanks ! Let's merge it after huggingface/transformers#26407 being merged