Multiple Browser Window Handling for Expired Link business migration / SAF

In user research, a participant had to use the expired link flow - she sent the email through the expired link modal and the expired link email opened a new browser window where the business appeared in the list, from there she used the manage business button (modal) to open the business, but then she used the first browser window to look at her business list and the page hadn't refreshed to show the business yet.

So in the original browser window it looks like the business was failed to be added.

**My Business Registry from the expired link affiliation modal ("second browser window"):**

**My Business Registry from original migration email ("first browser window") after she affiliated the business in the second browser window:**

We should look at solutions that would prevent the user thinking their business was not added properly.

Start by reproducing the expired-link affiliation flow across the two browser windows and compare the My Business Registry views described in the issue. Trace how the original window learns about the newly affiliated business; done should prevent it from appearing to fail, either by reflecting the affiliation or clearly communicating the current state.

Written by the indexing model from the issue text.