fix: 设备最后断开时间等于0

@@ -162,7 +162,9 @@ export const columns: BasicColumn[] = [
   {
     title: '最后断开时间',
     dataIndex: 'lastOfflineTime',
-    format: (text) => text && formatToDate(text, 'YYYY-MM-DD HH:mm:ss'),
+    format: (text) => {
+      return text ? formatToDate(text, 'YYYY-MM-DD HH:mm:ss') : '';
+    },
     width: 160,
   },
 ];