add torch_xla support in pipeline_stable_audio.py

[ghost]

What does this PR do?

Fixes # (issue)

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[hlky]

Thanks! 🤗

[ghost]

@hlky what is close-to-merge mean? when my source code can acturally merge into main branch?

[hlky]

@fancy45daddy It's an indicator for other reviewers that this PR is close to being merged, someone else will take a look then we'll get it in!

[ghost]

@hlky Do you have the ability to merge? I try to submit a lot of pr. But none of them are actually merge. How to accelerate the merge process? I need the code for my torch_xla project.

[hlky]

@fancy45daddy You can ping me on your other PRs for review if you like 🤗