Translation - Add Support for customized_attribution to translateDocument

[greese-insight]

Thanks for stopping by to let us know something could be better!

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Is your feature request related to a problem? Please describe.
We are attempting to apply a customized_attribution to the translateDocument method, but it is not available in the proto/interface.

Describe the solution you'd like
Have a way to set this field.

Describe alternatives you've considered
Requesting the api directly instead of using this package.

Additional context
Add any other context or screenshots about the feature request here.

[sofisl]

I've confirmed this is happening, we are updating our protos internally to include this feature.

[sofisl]

This was updated here: #4007. Please reopen if you're still seeing issues!