add back to countries list translation

I would have included this PR #5736, but that appears to be a commit that can go into 2-4-stable and master. This PR can only be merge with 2-4-stable.

There was a missing translation [here](https://github.com/spree/spree/blob/2-4-stable/backend/app/views/spree/admin/countries/edit.html.erb#L9) that I was unable to find in the locals.