Fix Multistore FF for empty DB - another way

What does this MR do and why?

Less invasive way to solve #346836 (closed), as an alternative to !75616 (closed)

How to set up and validate locally

RAILS_ENV=test bundle exec rake db:purge
RAILS_ENV=test bundle exec rake db:setup

will break on master, won't on this branch.

MR acceptance checklist

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Related to #346836 (closed)