fix(order):修复订单备注更新逻辑

- 移除了订单备注更新时的空字符串检查
- 允许将订单备注更新为空值
-保持了退款原因的非空检查逻辑不变

src/main/resources/mapper/OrderMapper.xml

@@ -171,7 +171,7 @@
             <if test="payPrice!= null ">
                 pay_price = #{payPrice},
             </if>
-            <if test="remark!= null and remark!= ''">
+            <if test="remark!= null">
                 remark = #{remark},
             </if>
             <if test="refundReason!= null and refundReason!= ''">