[Optimize]优化集群Brokers中, Controller显示存在延迟的问题 (#1162)

优化方式：
从DB获取调整为从Kafka中实时获取。

km-rest/src/main/java/com/xiaojukeji/know/streaming/km/rest/api/v3/cluster/ClusterBrokersController.java

@@ -52,7 +52,7 @@ public class ClusterBrokersController {
     @GetMapping(value = "clusters/{clusterPhyId}/brokers-state")
     @ResponseBody
     public Result<ClusterBrokersStateVO> getClusterPhyBrokersState(@PathVariable Long clusterPhyId) {
-        return Result.buildSuc(clusterBrokersManager.getClusterPhyBrokersState(clusterPhyId));
+        return clusterBrokersManager.getClusterPhyBrokersState(clusterPhyId);
     }
 
     @ApiOperation(value = "集群brokers信息列表")