98828 Add initial RUM implementation - form 10-10d

[michaelclement]

Are you removing, renaming or moving a folder in this PR?

• No, I'm not changing any folders (skip to TeamSites and delete the rest of this section)
• Yes, I'm removing, renaming or moving a folder

Did you change site-wide styles, platform utilities or other infrastructure?

• No
• Yes, and I used the proxy-rewrite steps to test the injected header scenario

Summary

This PR adds the RUM initialization to form 10-10d so it can be monitored in this dashboard. Feature is behind a flipper (matching BE PR) so it can be first tested in staging.

Related issue(s)

• Monitoring: RUM dashboard setup va.gov-team#98828
• 98828 Add feature toggle for RUM - form 10-10d vets-api#20038

Testing done

• Unit

Screenshots

NA

What areas of the site does it impact?

This form only.

Acceptance criteria

Quality Assurance & Testing

• I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• 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

NA

[michaelclement]

Adds RUM initialization function (modified from EZR form example).

[michaelclement]

Defaulting to 100% because we need to test in staging. Once we decide to start using in prod, this will have to change to a significantly reduced percentage.

[michaelclement]

Helper used later with useMemo to get relevant feature toggle state