Fix std initialization in Idefics variants
Author: yaswanth19
Pull request: yes

# What does this PR do?

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Fixes # (issue)


## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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## Who can review?

@zucchini-nlp A small review here for this nit fix PR

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Comments:
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@zucchini-nlp Done with the changes, No tests were failing and it just caught my eye when working on another PR.