AUTH UI - updates to bus reg page

Implement designs from UI design ticket.

How can we update this now that we have Coop IAs? And SP/GPs coming.

Remove the Incorporate a named benefit company?
Remove the Incorporate a numbered benefit company (if we have the incorporate numbered co section on the my bus dashboard)?
Add the Incorporate a cooperative association button?

No files or tests are named. Locate the AUTH UI business registration page and the referenced UI design ticket first; done means the page reflects the requested cooperative-association option and the decisions about named and numbered benefit-company options.

Written by the indexing model from the issue text.