DT-1206: Bug fixes for support requests

[rushtong]

Addresses

https://broadworkbench.atlassian.net/browse/DT-1206

Summary

This PR handles a couple of overlooked bugs

• Fix the return format the upload token to be a valid json object instead of a plain string
• Handle the Zendesk error case of UnprocessableEntityException when a normally well-formed ticket object cannot be processed by Zendesk due to invalid data

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