fix: don't set default payment amount in case of invoice return (backport #35645) (#35647)

fix: don't set default payment amount in case of invoice return (#35645)

(cherry picked from commit 79483cc90eb71fa82d645b2cf54d9731502cf6c7)

Co-authored-by: Anand Baburajan <anandbaburajan@gmail.com>
diff --git a/erpnext/public/js/controllers/taxes_and_totals.js b/erpnext/public/js/controllers/taxes_and_totals.js
index fd961c4..6f4e602 100644
--- a/erpnext/public/js/controllers/taxes_and_totals.js
+++ b/erpnext/public/js/controllers/taxes_and_totals.js
@@ -805,11 +805,13 @@
 			);
 		}
 
-		this.frm.doc.payments.find(pay => {
-			if (pay.default) {
-				pay.amount = total_amount_to_pay;
-			}
-		});
+		if(!this.frm.doc.is_return){
+			this.frm.doc.payments.find(payment => {
+				if (payment.default) {
+					payment.amount = total_amount_to_pay;
+				}
+			});
+		}
 
 		this.frm.refresh_fields();
 	}