Add additional ADP Workforce Now actions

## Summary

PR #20527 adds three read-only ADP WFN actions (Get Worker, Get Workers, Get Worker Demographics). This issue tracks one additional action covered by the same canonical scopes.

## Suggested Action

| Action | Endpoint | Use Case |
|--------|----------|----------|
| List Worker Demographics | `GET /hr/v2/worker-demographics` | Retrieve demographics for all workers (the PR only covers single-worker lookup by `{aoid}`) |

## Notes

- Work assignment data (job title, department, manager) and custom fields are already returned as part of the `GET /hr/v2/workers/{aoid}` response — no separate actions needed.