Fix Percent Billed to show Percentage

Previously was showing Currency

erpnext/stock/doctype/delivery_note/delivery_note.json

@@ -2216,7 +2216,7 @@
    "bold": 0, 
    "collapsible": 0, 
    "fieldname": "per_billed", 
-   "fieldtype": "Currency", 
+   "fieldtype": "Percent", 
    "hidden": 0, 
    "ignore_user_permissions": 0, 
    "ignore_xss_filter": 0, 
@@ -2914,4 +2914,4 @@
  "timeline_field": "customer", 
  "title_field": "title", 
  "track_seen": 0
-}
+}