[fix] if is_root is true make parent account empty (#12255)

diff --git a/erpnext/accounts/utils.py b/erpnext/accounts/utils.py
index 8cf1f51..e5809fe 100644
--- a/erpnext/accounts/utils.py
+++ b/erpnext/accounts/utils.py
@@ -252,6 +252,9 @@
 	if not ac.parent_account:
 		ac.parent_account = args.get("parent")
 
+	if ac.is_root:
+		ac.parent_account=''
+
 	ac.old_parent = ""
 	ac.freeze_account = "No"
 	if cint(ac.get("is_root")):