Enable AzureML logging for validation too

[tholop]

Before submitting

• [ ] (No, it's a minor edit) Was this discussed/approved via a Github issue? (no need for typos, doc improvements)
• [x] Did you read the contributor guideline?
• [x] Did you make sure to update the docs?
• [x] Did you write any new necessary tests?

What does this PR do?

The azureml-logging option is only working during the training loop, here: https://github.com/facebookresearch/fairseq/blob/ad3bec5a07962a994ac25ad1609ab926b13e0c0f/fairseq_cli/train.py#L298

This option does not work during the validation loop, and metrics don't appear in AzureML, because progress_bar doesn't get the azureml_logging argument: https://github.com/facebookresearch/fairseq/blob/ad3bec5a07962a994ac25ad1609ab926b13e0c0f/fairseq_cli/train.py#L491

This PR fixes that issue. I tested the patch on AzureML.

Did you have fun?

Yes!