Fix `SpeechT5ForSpeechToSpeechIntegrationTests` device issue
# What does this PR do?

Just a torch device issue being ifxed.
_The documentation is not available anymore as the PR was closed or merged._<|||||>Ah yes, nice catch. I don't have merge rights though.

Could you also fix this in modeling_speecht5? I think that has the same issue. Around line 2871:

```python
        if speaker_embeddings is None:
            speaker_embeddings = torch.zeros((1, 512), device=input_values.device)
```

Thanks!
<|||||>> Could you also fix this in modeling_speecht5? I think that has the same issue. Around line 2871:

Done!

> Ah yes, nice catch. I don't have merge rights though.

You have approval right :-) @hollance Then I can merge 🚀 

