fix: Make Sales Invoice paid when it create from shopping cart (#20879)

Co-authored-by: Saqib <nextchamp.saqib@gmail.com>
diff --git a/erpnext/accounts/doctype/payment_request/payment_request.py b/erpnext/accounts/doctype/payment_request/payment_request.py
index 5a0d092..53ff222 100644
--- a/erpnext/accounts/doctype/payment_request/payment_request.py
+++ b/erpnext/accounts/doctype/payment_request/payment_request.py
@@ -90,6 +90,7 @@
 		if (hasattr(ref_doc, "order_type") and getattr(ref_doc, "order_type") == "Shopping Cart"):
 			from erpnext.selling.doctype.sales_order.sales_order import make_sales_invoice
 			si = make_sales_invoice(self.reference_name, ignore_permissions=True)
+			si.allocate_advances_automatically = True
 			si = si.insert(ignore_permissions=True)
 			si.submit()