fix bug of Attention.head_to_batch_dim issue #10303

[Dawn-LX]

What does this PR do?

Fixes issue #10303

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  • issue 【BUG】Attention.head_to_batch_dim has bug in terms of tensor permutation #10303
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[hlky]

Thanks @Dawn-LX. I'll look into the test failures https://github.com/huggingface/diffusers/actions/runs/12431089601/job/34707874599?pr=10312
cc @yiyixuxu @sayakpaul

[hlky]

@Dawn-LX Can you confirm there is some case where the output shape as it was is incorrect? From the failing tests it looks like the comment is wrong.