Modular m4t speecht5 sew

[nikosanto13]

What does this PR do?

Completes the effort of #35902, by adding modular files for SEW, SEW-D, SeamlessM4T, SpeechT5 (as proposed by @eustlb)

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?

@eustlb

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