fix training issues

[ArthurZucker]

What does this PR do?

Fixes #35990! Paligemma did not have past_key_values

[ArthurZucker]

cc @muellerzr and @SunMarc WDYT about just by default setting this for all PreTrainedModels? (If we forget about it, people are not bothered

[HuggingFaceDocBuilderDev]

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[SunMarc]

Yeah sounds good to me @ArthurZucker. Maybe we can put it here since we only use it in trainer. This way, we don't add it in the config of models that potentially dont need it.

        if ignore_keys is None:
            if hasattr(self.model, "config"):
                ignore_keys = getattr(self.model.config, "keys_to_ignore_at_inference", ["past_key_values"])

[SunMarc]

Thanks a lot !