As it is just one line you can do it manually by editing /usr/share/gems/gems/foreman_host_extra_validator-0.2.1/db/migrate/20220923181701_fix_extra_validation_settings_category_to_dsl.rb and add if column_exists?(:settings, :category) to the line 3, afterwards you should be able to successfully run foreman-rake db:migrate.
Release done, Packaging in nightly done, Backport to 3.8 and 3.9 are currently running tests, so I hope the fixed version is available soon via packages!