Fix VLM generation issues
Author: ArthurZucker
Pull request: yes

# What does this PR do?
Fixes generation for llava-next-video. Apparently started failing after we moved to cache class but some parts of the code were not modified. Checked all llava models, others are working since check is done on a different condition.

Yes, we can start using cache_position and rely on that, but we should note that cache_position for VLMs will not be correct and will contain positions only for text tokens. Adding support for cache position will come in the next PR, which is in progress. We;ll have to deprecate many things before we can get rid of the current checks to "merge or expand".

This PR ports the changes from #32527 to a proper patch

## Before submitting
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## Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
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Comments:
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