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- [ ] I have searched the [issues](https://github.com/apache/dubbo/issues) of this repository and believe that this is not a duplicate.

## Describe the proposal
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EN:
Observability task, optimizing thread pool index embedding function
1 Need to specify a name for the core thread pool
2 Core thread pool index is not effective
3. Remove the frame-level indicators and only keep the core monitoring indicators (the frame-level code type is completely deleted and will be considered later)

可观测性任务，优化线程池指标埋点功能
1需要为核心线程池指定名称
2核心线程池指标生效问题
3移除框架层指标只保留核心监控指标
.findAny().orElse(null);
        }
        return threadNum;
    }
    private Integer getReferThreadNum() {
        Integer threadNum = null;
        ApplicationModel applicationModel = ApplicationModel.ofNullable(this.applicationModel);
        for (ModuleModel moduleModel : applicationModel.getPubModuleModels()) {
            threadNum = getReferThreadNum(moduleModel);
            if (threadNum != null) {
                break;
            }
        }
        if (threadNum == null) {
            logger.info("Cannot get config `refer-thread-num` from module config, using default: " + DEFAULT_REFER_THREAD_NUM);
            return DEFAULT_REFER_THREAD_NUM;
        }
        return threadNum;
    }
    private Integer getReferThreadNum(ModuleModel moduleModel) {
        ModuleConfig moduleConfig = moduleModel.getConfigManager().getModule().orElse(null);
        if (moduleConfig == null) {
            return null;
        }
        Integer threadNum = moduleConfig.getReferThreadNum();
        if (threadNum == null) {
            threadNum = moduleModel.getConfigManager().getConsumers()
                .stream()
                .map(ConsumerConfig::getReferThreadNum)
                .filter(k -> k != null && k > 0)