Emit '401-response-received' event on the dispatcher on 401 response in http/auth-gateway

## Emit '401-response-received' event on the dispatcher on 401 response in http/auth-gateway

The app can then listen and log out when this happens.

### Acceptance Criteria
1. Event is emitted whenever a request in http/auth-gateway returns a 401 response.

### Tasks
- Update http/auth-gateway

### Additional Notes
- None