Remove `task` arg in `load_dataset` in image-classification example
Author: regisss
Pull request: yes

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The `task` argument is now deprecated in the `datasets.load_dataset` method. This PR removes it and adds the renaming logic needed to deal with datasets like Cifar10 (the `task` attribute of datasets used to help with that).
Internal discussion here: https://huggingface.slack.com/archives/C034N0A7H09/p1704447848692889


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Comments:
Related to this PR, I opened an issue in `datasets` to improve the user experience when using `DatasetDict.column_names`:
- https://github.com/huggingface/datasets/issues/6571

The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_28408). All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

I think we should also add `image_column_name` (default `image`) and `label_column_name` (default `label`) to the example's `DataTrainingArguments` to be consistent with [`audio-classification`](https://github.com/huggingface/transformers/blob/357971ec367fecb9951ae3218feafece5f61416a/examples/pytorch/audio-classification/run_audio_classification.py#L95-L101) as renaming `img` to `image` is not general enough.

Thanks @regisss