Fix form dig, and add metrics for flashes.

[dfitchett]

Summary

• This work is behind a feature toggle (flipper): NO
• Fixes a form 526 dig to get flashes and adds metrics for flashes added to claims
• On submission of 526 form, we attempt to check flashes to see if it includes a particular flash on the claim.
• I'm on the Employee Experience team; we work with the Disability Experience team which maintains Form 526.

Related issue(s)

• Follow on to initially adding ALS flash capability for:
  • https://github.com/department-of-veterans-affairs/abd-vro/issues/3667

Testing done

• [x] New code is covered by unit tests
• Old behavior:
  • Incorrect dig to get flashes resulting in always having empty array of flashes and never logging statement
• New behavior:
  • correct form dig
  • logs list of flashes along with submitted claim id if a flash prototype is in the list of flashes. Only current prototype is Amyotrophic Lateral Sclerosis flash and is behind the feature flag disability_526_ee_process_als_flash and is not enabled in production
  • pushes an increment to datadog for each flash, prototype or not
  • this will allow gathering metrics for flashes applied via va.gov form 526 submission

What areas of the site does it impact?

• no user functionality is affected
• metrics in datadog will be available on this dashboard

Acceptance criteria

• [x] I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• [x] No error nor warning in the console.
• [x] Events are being sent to the appropriate logging solution