Create UI - in amalg attempting to add an unaffiliated business breaks UI

Steps to reproduce:
- sign in as a regular user (non staff)
- start a horizontal amalg
- attempt to add a modernized amalgamating business that is not affiliated with the account
- loading screen is indefinite and requires reloading the page (unsaved changes will be lost)

Notes:
- colin business flow will allow you to add the business and shows a warning for you to affiliate
- marking an unaffiliated business as primary will give a generic error modal - suggest changing this to let the user know they need to affiliate it with a link to the dashboard that auto opens the affiliation modal