FIX [`quantization` / `ESM`] Fix ESM 8bit / 4bit with bitsandbytes (#29329)
* fix ESM 8bit
* Apply suggestions from code review
Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>
* fixup
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Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>