修复共富商户为空

pjcloud-supermarket/pjcloud-supermarket-biz/src/main/java/com/bsd/pjcloud/supermarket/controller/MallAppController.java

@@ -121,7 +121,7 @@ public class MallAppController {
             return R.failed("商户服务异常！");
         }
         List<MchManageVo> merchants = listR.getData();
-        if (merchants.isEmpty()) {
+        if (CollectionUtils.isEmpty( merchants)) {
             return R.ok(List.of());
         }