### Environment

* Dubbo version: dubbo-registry-nacos 2.7.6
* Operating System version: Win10
* Java version: JAVA 8

### Steps to reproduce this issue
1 springboot  yml配置如下： 
registry:
     address: nacos://127.0.0.1:8848
     simplified: true
     group: dubbo-local
  metadata-report:
            address: nacos://127.0.0.1:8848
            group: dubbo-local

2 登陆nacos 1.2.1 控制台发现元数据 group配置生效，但是服务管理下的group依旧是DEFAULT_GROUP。

3 跟了下dubbo-registry-nacos 2.7.6的代码 发现在调用NamingService中 没有传入配置的group参数，使用的默认组参数 
 public void doRegister(URL url) {
        String serviceName = this.getServiceName(url);
        Instance instance = this.createInstance(url);
        this.execute((namingService) -> {
            namingService.registerInstance(serviceName, instance);
        });
    }

Pls. provide [GitHub address] to reproduce this issue.

### Expected Result

What do you expected from the above steps？

### Actual Result

What actually happens?

If there is an exception, please attach the exception trace:

```
Just put your stack trace here!
```

newURL = newURL.addParameter(PATH_KEY, url.getPath());
        String ip = url.getHost();
        int port = url.getPort();
        Instance instance = new Instance();
        instance.setIp(ip);
        instance.setPort(port);
        instance.setMetadata(new HashMap<>(newURL.getParameters()));
        return instance;
    }
    private NacosServiceName createServiceName(URL url) {
        return valueOf(url);
    }
    private String getServiceName(URL url) {
        return getServiceName(url, url.getParameter(CATEGORY_KEY, DEFAULT_CATEGORY));
    }
    private String getServiceName(URL url, String category) {
        return category + SERVICE_NAME_SEPARATOR + url.getColonSeparatedKey();
    }
    private void execute(NamingServiceCallback callback) {
        try {
            callback.callback(namingService);
        } catch (NacosException e) {
            if (logger.isErrorEnabled()) {
                logger.error(e.getErrMsg(), e);
            }
        }
    }
    private void filterHealthyInstances(Collection<Instance> instances) {
        filterData(instances, Instance::isEnabled);
    }