nixos/gitlab: don't install pg_trgm for remote hosts

Fixes #41476

nixos/modules/services/misc/gitlab.nix

@@ -612,10 +612,11 @@ in {
             ${pkgs.sudo}/bin/sudo -u ${pgSuperUser} ${config.services.postgresql.package}/bin/createdb --owner ${cfg.databaseUsername} ${cfg.databaseName}
             touch "${cfg.statePath}/db-created"
           fi
-        fi
 
           # enable required pg_trgm extension for gitlab
           ${pkgs.sudo}/bin/sudo -u ${pgSuperUser} psql ${cfg.databaseName} -c "CREATE EXTENSION IF NOT EXISTS pg_trgm"
+        fi
+
         # Always do the db migrations just to be sure the database is up-to-date
         ${gitlab-rake}/bin/gitlab-rake db:migrate RAILS_ENV=production