Fix Qwen2VL processor to handle odd number of frames

[jla524]

What does this PR do?

Fixes #35412 (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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• Did you write any new necessary tests?

Who can review?

@ArthurZucker, @amyeroberts, @qubvel