feat: 优化 MerchantLogic.php 中 goods_id 对应的 nums 数据赋值逻辑，增加可空默认值

app/admin/logic/merchant/MerchantLogic.php

@@ -268,7 +268,7 @@ class MerchantLogic extends BaseLogic
                 $data = [
                     'mer_id' => $params['mer_id'],
                     'goods_id' => $v['goods_id'],
-                    'nums' => $v['nums']
+                    'nums' => $v['nums']??0
                 ];
                 $has = Db::name('merchant_bind_goods')->where('mer_id', $params['mer_id'])->where('goods_id', $v['goods_id'])->findOrEmpty();
                 if (!empty($has)) {