Use audio feature in ASR task template
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The AutomaticSpeechRecognition task template is outdated: it still uses the file path column as input instead of the audio column.

I changed that and updated all the datasets as well as the tests.

The only community dataset that will need to be updated is `facebook/multilingual_librispeech`. It has almost zero usage unfortunately (probably because users load the duplicate `multilingual_librispeech` directly instead), but it means we can update it.

(this makes me think that we should deprecate `multilingual_librispeech` it and redirect users to `facebook/multilingual_librispeech`).

This PR is also useful for the AudioFolder in https://github.com/huggingface/datasets/pull/3963