Fix the demo for the schools (#8879)

* Fix the demo for the schools

* Fix for the demo

https://github.com/frappe/erpnext/issues/6347
diff --git a/erpnext/demo/data/item_schools.json b/erpnext/demo/data/item_schools.json
index 5eb6082..077fcaa 100644
--- a/erpnext/demo/data/item_schools.json
+++ b/erpnext/demo/data/item_schools.json
@@ -57,6 +57,7 @@
  },
  {
   "is_stock_item": 0,
+  "default_warehouse": "Stores",
   "description": "Computer",
   "item_code": "Computer",
   "item_name": "Computer",
@@ -64,6 +65,7 @@
  },
  {
   "is_stock_item": 0,
+  "default_warehouse": "Stores",
   "description": "Mobile",
   "item_code": "Mobile",
   "item_name": "Mobile",
@@ -71,6 +73,7 @@
  },
  {
   "is_stock_item": 0,
+  "default_warehouse": "Stores",
   "description": "ERP",
   "item_code": "ERP",
   "item_name": "ERP",
@@ -78,6 +81,7 @@
  },
  {
   "is_stock_item": 0,
+  "default_warehouse": "Stores",
   "description": "Autocad",
   "item_code": "Autocad",
   "item_name": "Autocad",
@@ -85,6 +89,7 @@
  },
  {
   "default_warehouse": "Stores",
+  "default_warehouse": "Stores",
   "item_code": "Service",
   "item_group": "Services",
   "item_name": "Service",