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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
@Override
    public List<MetricSample> collect() {
        List<MetricSample> list = new ArrayList<>();
        for (MetricsSampler sampler : samplers) {
            List<MetricSample> sample = sampler.sample();
            list.addAll(sample);
        }
        return list;
    }
    public void addListener(MetricsListener listener) {
        this.eventMulticaster.addListener(listener);
    }
    public SimpleMetricsCountSampler<String, MetricsEvent.Type, ApplicationMetric> applicationSampler = new SimpleMetricsCountSampler<String, MetricsEvent.Type, ApplicationMetric>() {
        @Override
        public List<MetricSample> sample() {
            List<MetricSample> samples = new ArrayList<>();
            this.getCount(MetricsEvent.Type.APPLICATION_INFO).filter(e -> !e.isEmpty())
                .ifPresent(map -> map.forEach((k, v) ->
                    samples.add(new GaugeMetricSample<>(APPLICATION_METRIC_INFO, k.getTags(), APPLICATION, v, AtomicLong::get)))
                );
            return samples;
        }
        @Override
        protected void countConfigure(
            MetricsCountSampleConfigurer<String, MetricsEvent.Type, ApplicationMetric> sampleConfigure) {
            sampleConfigure.configureMetrics(configure -> new ApplicationMetric(sampleConfigure.getSource()));
        }
    };
}