certain settings should be decrypted for cache config migration to run (#44048)

resources/migrations/001_update_migrations.yaml

...s/migrations/custom_sql/fill_cache_config_root_fix.my.sql

src/metabase/db/custom_migrations.clj

test/metabase/db/custom_migrations_test.clj

test/metabase/db/schema_migrations_test.clj