perf: index dn_detail in Delivery Note Item (backport #37528) (#37530)

* perf: index `dn_detail` in `Delivery Note Item`

(cherry picked from commit 5b4528e614)

# Conflicts:
#	erpnext/stock/doctype/delivery_note_item/delivery_note_item.json

* chore: `conflicts`

---------

Co-authored-by: s-aga-r <sagarsharma.s312@gmail.com>

erpnext/stock/doctype/delivery_note_item/delivery_note_item.json

@@ -741,7 +741,8 @@
    "label": "Against Delivery Note Item",
    "no_copy": 1,
    "print_hide": 1,
-   "read_only": 1
+   "read_only": 1,
+   "search_index": 1
   },
   {
    "fieldname": "stock_qty_sec_break",
@@ -868,7 +869,7 @@
  "index_web_pages_for_search": 1,
  "istable": 1,
  "links": [],
- "modified": "2023-07-25 11:58:28.101919",
+ "modified": "2023-10-16 16:18:18.013379",
  "modified_by": "Administrator",
  "module": "Stock",
  "name": "Delivery Note Item",