Better Country Multi-Select

[RogerTangos]

AS A person using the bank green admin panel
I WANT a better way to select multiple countries for a brand
SO THAT I do not accidentally mess up a brand's countries

The default multi-select admin panel tool is a poor fit for countries. It makes it hard to see what countries are selected for a bank, difficult to find new countries, and easy to wipe the data that is there by accidentally selecting a single country

It would be much better to have a typing-search multi select field (if possible) or another custom widget. This documentation might be a good place to start.

Acceptance Criteria:

• There is another, better widget for selecting multiple countries
• The old country selector is gone from the brand page.