Policy User Role Selection

### Problem description
Currently, even if we have only one policy user configured in the policy, we need to create a role and select as PP explicitly.
This was a request from Verra.
### Requirements
1. We need to automatically configure if there is only one user in the policy configurator.
2. No need to select the role in UI.

### Definition of done
How do we know we've fully dealt with it?

### Acceptance criteria
What are the criteria by which we determine if the issue has been resolved?