Mirrors the same Provider & Location page pattern from the eligibility worker:
- wait for paymentGroupId label visibility before interacting
- Treatment Location: ng-arrow-wrapper click + ARROW_DOWN/ENTER
- Billing Entity: ng-arrow-wrapper click + ARROW_DOWN/ENTER
- re-find Continue button after selections to avoid stale element
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>