[DR-90265] Log error body to DataDog if Lighthouse returns 422

[anniebtran]

Summary

Currently we are using a Sentry log to help us figure out what field is causing a 422 error in our requests to Lighthouse, as there aren't details about it in our DataDog logs currently. Since we're moving away from using Sentry, we're appending the 422 error body to an error log we already send to DataDog.

Related issue(s)

department-of-veterans-affairs/va.gov-team#90265

Testing done

• New code is covered by unit tests

What areas of the site does it impact?

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

Acceptance criteria

• I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• Events are being sent to the appropriate logging solution
• No sensitive information (i.e. PII/credentials/internal URLs/etc.) is captured in logging, hardcoded, or specs