fix: Make expense account editable in Purchase Receipt Item (backport #31730) (#31879)

* fix: Make expense account editable in Purchase Receipt Item (#31730)

Co-authored-by: Sagar Sharma <sagarsharma.s312@gmail.com>
(cherry picked from commit 1a6508972e)

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

* chore: conflicts

Co-authored-by: Deepesh Garg <deepeshgarg6@gmail.com>
Co-authored-by: Sagar Sharma <sagarsharma.s312@gmail.com>

erpnext/stock/doctype/purchase_receipt_item/purchase_receipt_item.json

@@ -786,10 +786,8 @@
   {
    "fieldname": "expense_account",
    "fieldtype": "Link",
-   "hidden": 1,
    "label": "Expense Account",
-   "options": "Account",
-   "read_only": 1
+   "options": "Account"
   },
   {
    "fieldname": "accounting_dimensions_section",
@@ -994,7 +992,7 @@
  "idx": 1,
  "istable": 1,
  "links": [],
- "modified": "2022-04-11 13:07:32.061402",
+ "modified": "2022-07-28 19:27:54.880781",
  "modified_by": "Administrator",
  "module": "Stock",
  "name": "Purchase Receipt Item",