properly show error

stock/static/js/stock_movements.js

@@ -707,7 +707,9 @@ function do_stock_movement() {
 
             },
             error: function(data) {
-                if(data.responseJSON.error == "Failed api execute : <Fault 2: \"Could not reserve all requested products. Please use the 'Mark as Todo' button to handle the reservation manually.\">")
+                let could_not_reserve_error = "Failed api execute : <Fault 2: \"Could not reserve all requested products. Please use the 'Mark as Todo' button to handle the reservation manually.\">";
+                if(data.responseJSON.errors.length > 0
+                    && data.responseJSON.errors[0] == could_not_reserve_error)
                 {
                     closeModal();
                     reset_focus();