feat: 更新 discountAmount 以使用 info.payAmount 的值

src/BIZComponents/paymentCollectionPlan/Index.vue

@@ -508,6 +508,7 @@
         // console.log(this.discountAmount, '77777');
         // console.log(val, '5555555');
         val = Number(val);
+        this.discountAmount = Number(this.info.payAmount);
         try {
           if (index != null) {
             await this.checkRatio();