dubbo泛化调用设置了group的提供者服务时，提示no provider，debug发现consul的健康检查不通过

- [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: 2.7.6
* Operating System version: win10
* Java version: 1.8

### Steps to reproduce this issue

1. 本地启动最简单的dubbo provider进程，注册中心选择consul
2. 本地单测通过dubbo泛化调步骤1的provider

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

### Expected Result

dubbo泛化正常

### Actual Result

若provider未设置group可正常调用；否则报“org.apache.dubbo.rpc.RpcException: No provider available from registry xxx for service group/service on consumer...”异常

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

```
org.apache.dubbo.rpc.RpcException: No provider available from registry localhost:8500 for service g1/fake.service.FakeService on consumer 172.28.42.23 use dubbo version 2.7.6, please check status of providers(disabled, not registered or in blacklist).
at org.apache.dubbo.registry.integration.RegistryDirectory.doList(RegistryDirectory.java:599)
at org.apache.dubbo.rpc.cluster.directory.AbstractDirectory.list(AbstractDirectory.java:75)
at org.apache.dubbo.rpc.cluster.support.AbstractClusterInvoker.list(AbstractClusterInvoker.java:291)
at org.apache.dubbo.rpc.cluster.support.AbstractClusterInvoker.invoke(AbstractClusterInvoker.java:256)
at org.apache.dubbo.rpc.cluster.interceptor.ClusterInterceptor.intercept(ClusterInterceptor.java:47)
at org.apache.dubbo.rpc.cluster.support.wrapper.AbstractCluster$InterceptorInvokerNode.invoke(AbstractCluster.java:92)
at org.apache.dubbo.rpc.cluster.support.wrapper.MockClusterInvoker.invoke(MockClusterInvoker.java:82)
at org.apache.dubbo.rpc.proxy.InvokerInvocationHandler.invoke(InvokerInvocationHandler.java:74)
at org.apache.dubbo.common.bytecode.proxy0.$invoke(proxy0.java)
at dubbo.DubboTest.invoke(DubboTest.java:65)

```

Reproduce the issue with Dubbo 2.7.6 using a local provider, Consul, and a configured group, following the two listed steps. Start at RegistryDirectory.doList and the registry integration path shown in the stack trace, then inspect how grouped providers are discovered during generic invocation. Done means the grouped provider is discoverable and the generic call no longer reports No provider.

Written by the indexing model from the issue text.