Add prefill for form 26-4555 Adapted housing

[gmrabian]

Enables prefill for form 26-4555 as per the VA documentation

Summary

• Add form to forms list and class list
• Create form model class
• Create form profile mapping yml
• Enable prefill in settings
• Add tests

Related issue(s)

• Va Forms team: https://app.zenhub.com/workspaces/vagov-product-team-forms-634853151f5c6000165942bc/issues/gh/department-of-veterans-affairs/va.gov-team-forms/20

Testing done

• Tested locally with backend and ui running - prefill worked successfully.
• Ran added rspec test and it passed

What areas of the site does it impact?

Forms

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