[SIMPLE-FORMS] feat: update 4138 confirmation page to use new page design

[pennja]

Summary

• This work updates form 21-4138 to use the updated confirmation page design.
• I'm a member of the Veteran Facing Forms team who owns this page.

Related issue(s)

• department-of-veterans-affairs/va.gov-team-forms#1975

Testing done

• Unit and E2E tests pass.

Screenshots

	Before	After
Mobile
Desktop

Acceptance criteria

Quality Assurance & Testing

• No sensitive information (i.e. PII/credentials/internal URLs/etc.) is captured in logging, hardcoded, or specs
• Linting warnings have been addressed
• Documentation has been updated (link to documentation *if necessary)
• Screenshot of the developed feature is added
• Accessibility testing has been performed

Error Handling

• Browser console contains no warnings or errors.
• Events are being sent to the appropriate logging solution
• Feature/bug has a monitor built into Datadog or Grafana (if applicable)

Authentication

• Did you login to a local build and verify all authenticated routes work as expected with a test user

Requested Feedback

Any