fix: allow on submit for the delivery date field

erpnext/selling/doctype/sales_order_item/sales_order_item.json

@@ -1,4 +1,5 @@
 {
+ "actions": [],
  "autoname": "hash",
  "creation": "2013-03-07 11:42:58",
  "doctype": "DocType",
@@ -151,6 +152,7 @@
    "width": "300px"
   },
   {
+   "allow_on_submit": 1,
    "columns": 2,
    "depends_on": "eval: !parent.skip_delivery_note",
    "fieldname": "delivery_date",
@@ -767,7 +769,8 @@
  ],
  "idx": 1,
  "istable": 1,
- "modified": "2019-12-12 18:06:26.238169",
+ "links": [],
+ "modified": "2020-01-13 12:29:03.103797",
  "modified_by": "Administrator",
  "module": "Selling",
  "name": "Sales Order Item",