Port Duo Chat CEF testing from REST API to GraphQL to Capture Source References

Problem

We recently released a change in the documentation tool that lead to a problem that was not discovered by CEF because CEF is not aware of source references in the answer: #464461 (closed)

In the CEF, Duo Chat answers to documentation-related question do not contain source references as they are not supported by the REST API. The work in this issue would ensure validation reponse parity with production.

Proposal

• Port Duo Chat from the REST API to GraphQL such that source references are tracked and rated by CEF.
• Create a different user account for Duo Chat tests to get around the per user limit