Restore missed expectation

A previous pull request re-wrote this spec but omitted the main
expectation of this spec block.

* https://github.com/openfoodfoundation/openfoodnetwork/pull/11852/files

spec/system/admin/order_cycles/simple_spec.rb

@@ -488,6 +488,7 @@ RSpec.describe '
           expect(page).to have_content v1.product.name
 
           expect(page).not_to have_content "No variant available for this product"
+          expect(page).to have_content "(Some variants might be hidden via inventory settings)"
         end
       end