Implements new endpoint behind feature flag

[tyler-spangler6]

Note: Delete the description statements, complete each step. None are optional, but can be justified as to why they cannot be completed as written. Provide known gaps to testing that may raise the risk of merging to production.

Summary

• This work is behind a feature toggle (flipper): YES
• This adds a new endpoint to the Virtual Regional Office client to perform contention classification using a new method
• The call to the new end point called behind a feature flag that we plan to increase traffic to incrementally to test the response and response time

Related issue(s)

• https://github.com/orgs/department-of-veterans-affairs/projects/873/views/2?pane=issue&itemId=85258469&issue=department-of-veterans-affairs%7Cvagov-claim-classification%7C626

Testing done

• New code is covered by unit tests
• Tests are written for the toggle on and off and is based on the user to plan for an incremental release
• VCR cassettes are included for both the default classification and the method to test which endpoint is being called
• If this work is behind a flipper:
  • Tests need to be written for both the flipper on and flipper off scenarios. Docs.
  • What is the testing plan for rolling out the feature?
  • We plan to start by testing in staging and then doing a phased rollout to a small percentage of users

Screenshots

Note: Optional

What areas of the site does it impact?

(Describe what parts of the site are impacted andifcode touched other areas)

Acceptance criteria

• I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• No error nor warning in the console.
• Events are being sent to the appropriate logging solution
• Documentation has been updated (link to documentation)
• No sensitive information (i.e. PII/credentials/internal URLs/etc.) is captured in logging, hardcoded, or specs
• Feature/bug has a monitor built into Datadog (if applicable)
• If app impacted requires authentication, did you login to a local build and verify all authenticated routes work as expected
• I added a screenshot of the developed feature

Requested Feedback

(OPTIONAL)What should the reviewers know in addition to the above. Is there anything specific you wish the reviewer to assist with. Do you have any concerns with this PR, why?

[williamphelps13]

LGTM just a comment on an alternative implementation with pros and cons:

[nanotone]

Looks good to me!

[rmtolmach]

👍 requested changes made. One last comment, but not blocking. Just keep in mind if you see any flakeyness.

[rmtolmach]

If any test flakeyness shows up, these could be the culprit.

[github-actions]

Backend-review-group approval confirmed.