Add AutoProcessor registration

[petersalas]

UV 0.4 doesn't currently register the processor.

[farzadab]

Oh good catch.
That's so confusing. You'd think AutoProcessor.register is enough, but I guess it's not.

[farzadab]

Actually, looking at the code of ultravox_processing.py, I don't see from_pretraiend which suggests that I didn't use main branch to push the model.

[farzadab]

@petersalas will you update the two files (ultravox_processin.py and config.json) on ultravox-v0_4 or should I?
It's possible that we didn't need the extra register tbh.

[petersalas]

Oh I see -- do you have (can you land) the other changes we need for from_pretrained?

[farzadab]

Done.