Investigate service fee integration for Continuation In Application

Currently there is no mechanism in place to show the service fee on the Continuation In Application. In sbc-pay, service fees are hard-coded to not display for any staff user.

We need to investigate how we can integrate the service fee into the Continuation In Application flow, including:

- How the service fee should be surfaced in the Fee Summary for Continuation Applications
- What changes are needed in sbc-pay, where the current hard-coded behaviour suppresses the service fee for staff
- Any impacts to business-create-ui (fee summary display, staff payment component)