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

### Environment

* Dubbo version: 2.7.2
* Operating System version: macOS 10.12.6
* Java version: 1.8

### Steps to reproduce this issue



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

### Expected Result

What do you expected from the above steps？

```java

    ZookeeperDynamicConfiguration(URL url, ZookeeperTransporter zookeeperTransporter) {
        this.url = url;
        rootPath = "/" + url.getParameter(CONFIG_NAMESPACE_KEY, DEFAULT_GROUP) + "/config";

        initializedLatch = new CountDownLatch(1);
        this.cacheListener = new CacheListener(rootPath, initializedLatch);
        this.executor = Executors.newFixedThreadPool(1, new NamedThreadFactory(this.getClass().getSimpleName(), true));

        zkClient = zookeeperTransporter.connect(url);
        zkClient.addDataListener(rootPath, cacheListener, executor);
        try {
            // Wait for connection
            this.initializedLatch.await();
        } catch (InterruptedException e) {
            logger.warn("Failed to build local cache for config center (zookeeper)." + url);
        }
    }
```

`        zkClient = zookeeperTransporter.connect(url);`会通过URL中的client参数来正确选择自适应扩展来初始化zk客户端。但在初始化配置中心的时候，URL是由ConfigCenterConfig得到的，此时URL中无client的信息，所以这个地方创建zk还是用的默认的zkClient。希望和注册中心时候一样获取自己扩展的zkClient


### Actual Result

What actually happens?

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

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

import org.apache.dubbo.common.utils.Assert;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.common.utils.ConfigUtils;
import org.apache.dubbo.common.utils.NetUtils;
import org.apache.dubbo.common.utils.ReflectUtils;
import org.apache.dubbo.common.utils.StringUtils;
import org.apache.dubbo.common.utils.UrlUtils;
import org.apache.dubbo.config.context.ConfigManager;
import org.apache.dubbo.config.support.Parameter;
import org.apache.dubbo.configcenter.DynamicConfiguration;
import org.apache.dubbo.configcenter.DynamicConfigurationFactory;
import org.apache.dubbo.metadata.integration.MetadataReportService;
import org.apache.dubbo.monitor.MonitorFactory;
import org.apache.dubbo.monitor.MonitorService;
import org.apache.dubbo.registry.RegistryService;
import org.apache.dubbo.rpc.Filter;
import org.apache.dubbo.rpc.InvokerListener;
import org.apache.dubbo.rpc.ProxyFactory;
import org.apache.dubbo.rpc.cluster.Cluster;
import org.apache.dubbo.rpc.model.ApplicationModel;
import org.apache.dubbo.rpc.support.MockInvoker;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import static org.apache.dubbo.common.config.ConfigurationUtils.parseProperties;