fix ValueError message in LlamaAttention
Author: othertea
Pull request: yes

# What does this PR do?

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Fixes #22941


## Before submitting
- [x] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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- [ ] Did you write any new necessary tests?


## Who can review?

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Models:

- text models: @ArthurZucker and @younesbelkada
- vision models: @amyeroberts
- speech models: @sanchit-gandhi
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Library:

- flax: @sanchit-gandhi
- generate: @gante
- pipelines: @Narsil
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- tokenizers: @ArthurZucker
- trainer: @sgugger

Integrations:

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- rust tokenizers: [different repo](https://github.com/huggingface/tokenizers)

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Comments:
_The documentation is not available anymore as the PR was closed or merged._