用nacos作为注册中心，consumer报no provider

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

### Environment

* Dubbo version: 2.7.18
* Operating System version: Ubuntu 20.04.5 LTS
* Java version: 1.8.0_202

### Steps to reproduce this issue

1. 配置dubboreference
2. 启动服务
3. 调用服务，报no provider

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

### 服务调用成功

### 调用异常，报no provider

1. 服务启动时，服务注册consumer后 , dubbo收到nacos下发的当前服务的consumer信息变更事件，dubbo会用empty协议的本地provider变更服务provider注册信息
2. 如果此事件处理在正常实例下发事件处理之后，此时变更实例数为1，导致注册中的forbidden设置为true;则后续调用会产生no provider异常。


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Just put your stack trace here!
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