[feat]修改预警启动报错

dk-modules/business/src/main/java/org/dromara/business/service/impl/BusinessAlertServiceImpl.java

@@ -532,7 +532,7 @@ public class BusinessAlertServiceImpl implements IBusinessAlertService {
         } catch (Exception e) {
             e.printStackTrace();
         }
-        return null;
+        return TableDataInfo.build();
     }