Api 24364 improve validation for survivor

[mchristiansonVA]

Summary

• Improved validation for ITF type "survivor", adding a check for blank "claimantSsn" parameter for the /validate and /intent-to-file endpoints when the type parameter is "survivor".
• Note that this validation does not apply to the /type endpoint, which finds the active ITF record for the specified type, as the normal use cases for that endpoint would include ITF type "survivor" without supplying a "claimantSsn" parameter.
• Note that both /intent-to-file and /validate POSTs for type "survivor" but without a "claimantSsn" parameter respond with HTTP 422 Unprocessable entity.

Related issue(s)

• API-24364

Testing done

• Tested the /validate endpoint to confirm it returns an appropriate error for type "survivor" with no "claimantSsn" parameter supplied.
• Tested the /intent-to-file endpoint to confirm it returns an appropriate error for type "survivor" with no "claimantSsn" parameter supplied.
• Tested the /type endpoint to confirm it returns appropriate results for type "survivor" with no "claimantSsn" parameter supplied.
• Updated and added rspec tests for new cases.

What areas of the site does it impact?

• vets-api Intent To File endpoint validation.

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 or Grafana (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

[stiehlrod]

LGTM. Tested in Sandbox with and without claimant SSN