The integration of Seata with the Nacos module: No available service

**Which Component**

Spring Cloud Alibaba: `2022.0.0.0-RC1`, Seata: `1.7.0-SNAPSHOT`, Nacos Client: `2.2.1-RC`, Nacos Server: `1.4.x` or `2.x`



**Describe the bug**

1. Tests were conducted using the Seata `master (1.6.1)` branch and the functionality is work. 

2. When using the Seata `develop (1.7.0-SNAPSHOT)` branch code, an exception will be thrown: "No available service"



**To Reproduce**

1. Building using the Seata `develop` branch code: `mvn clean install -Dmaven.test.skip=true`

3. Modifying the `pom.xml` file in the `spring-cloud-alibaba-dependencies` module (only for testing purposes):

```xml

<sentinel.version>1.7.0-SNAPSHOT</sentinel.version>

```

4. Starting the necessary services based on the `readme-zh.md` in the examples section.

See examples: https://github.com/alibaba/spring-cloud-alibaba/tree/2022.x/spring-cloud-alibaba-examples/seata-example

5. Call `http://127.0.0.1:18081/seata/feign`, and you will see the following exception message: 

```java

2023-02-06T21:30:55.744+08:00  WARN 29612 --- [io-18081-exec-1] ServiceLoader$InnerEnhancedServiceLoader : Load [io.seata.core.context.ContextCore] class fail: no service files found in 'META-INF/seata/'.

2023-02-06T21:30:55.745+08:00 DEBUG 29612 --- [io-18081-exec-1] .s.i.h.TransactionPropagationInterceptor : xid in RootContext[null] xid in HttpContext[null]

2023-02-06T21:30:55.758+08:00  WARN 29612 --- [io-18081-exec-1] ServiceLoader$InnerEnhancedServiceLoader : Load [io.seata.core.model.TransactionManager] class fail: no service files found in 'META-INF/seata/'.

2023-02-06T21:30:55.758+08:00  INFO 29612 --- [io-18081-exec-1] io.seata.tm.TransactionManagerHolder     : TransactionManager Singleton io.seata.tm.DefaultTransactionManager@69f929b1

2023-02-06T21:30:55.762+08:00 ERROR 29612 --- [io-18081-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: io.seata.common.exception.FrameworkException: No available service] with root cause



io.seata.common.exception.FrameworkException: No available service

	at io.seata.core.rpc.netty.AbstractNettyRemotingClient.loadBalance(AbstractNettyRemotingClient.java:266) ~[seata-all-1.6.1.jar:1.6.1]

	at io.seata.core.rpc.netty.AbstractNettyRemotingClient.sendSyncRequest(AbstractNettyRemotingClient.java:142) ~[seata-all-1.6.1.jar:1.6.1]

	at io.seata.tm.DefaultTransactionManager.syncCall(DefaultTransactionManager.java:95) ~[seata-all-1.6.1.jar:1.6.1]

	at io.seata.tm.DefaultTransactionManager.begin(DefaultTransactionManager.java:53) ~[seata-all-1.6.1.jar:1.6.1]

	at io.seata.tm.api.DefaultGlobalTransaction.begin(DefaultGlobalTransaction.java:114) ~[seata-all-1.6.1.jar:1.6.1]

	at io.seata.tm.api.TransactionalTemplate.beginTransaction(TransactionalTemplate.java:250) ~[seata-all-1.6.1.jar:1.6.1]

	at io.seata.tm.api.TransactionalTemplate.execute(TransactionalTemplate.java:125) ~[seata-all-1.6.1.jar:1.6.1]

	at io.seata.spring.annotation.GlobalTransactionalInterceptor.handleGlobalTransaction(GlobalTransactionalInterceptor.java:201) ~[seata-all-1.6.1.jar:1.6.1]

	at io.seata.spring.annotation.GlobalTransactionalInterceptor.invoke(GlobalTransactionalInterceptor.java:171) ~[seata-all-1.6.1.jar:1.6.1]

......



2023-02-06T21:30:55.769+08:00 DEBUG 29612 --- [io-18081-exec-1] .s.i.h.TransactionPropagationInterceptor : xid in RootContext[null] xid in HttpContext[null]

2023-02-06T21:31:40.685+08:00 ERROR 29612 --- [eoutChecker_1_1] i.s.c.r.netty.NettyClientChannelManager  : no available service found in cluster 'default', please make sure registry config correct and keep your seata server running

2023-02-06T21:31:40.934+08:00 ERROR 29612 --- [eoutChecker_2_1] i.s.c.r.netty.NettyClientChannelManager  : no available service found in cluster 'default', please make sure registry config correct and keep your seata server running

2023-02-06T21:31:50.697+08:00 ERROR 29612 --- [eoutChecker_1_1] i.s.c.r.netty.NettyClientChannelManager  : no available service found in cluster 'default', please make sure registry config correct and keep your seata server running

```





`AbstractNettyRemotingClient.java`

```java

    protected String loadBalance(String transactionServiceGroup, Object msg) {

        InetSocketAddress address = null;

        try {

            @SuppressWarnings("unchecked")

            List<InetSocketAddress> inetSocketAddressList = RegistryFactory.getInstance().aliveLookup(transactionServiceGroup);

            address = this.doSelect(inetSocketAddressList, msg);

        } catch (Exception ex) {

            LOGGER.error(ex.getMessage());

        }

    }

```

It seems that `RegistryFactory.getInstance().aliveLookup(transactionServiceGroup)` is unable to discover other services.

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