[Docs] Translate audio_classification.md from English to Spanish (#39513)
* Docs: translate audio_classification to Spanish
* Update audio_classification.md
* Remove space
* Normalize backticks
* Update audio_classification.md
* Apply corrections recommended by aaronjimv
* Update _toctree.yml
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Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>