Can't start normally when use nacosRegistry even provider already register.

[horizonzy]

Environment

• Dubbo version: master

Steps to reproduce this issue

1. modify dubbo-demo-xml-consumer/spring/dubbo-consumer.xml
   2.start dubbo-demo-xml-consumer/Application

Expected Result

in migrationInvoker.migrateToServiceDiscoveryInvoker(false);
first call refreshServiceDiscoveryInvoker(), in the process, it will use metadataReport, but nacosMetadataReport didn't support
service app mapping, so the serviceName is empty, and check is true, then throw the exception.

If fact, refreshInterfaceInvoker() will create invoker normally.

So the check should consider both situaion.

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

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'demoService': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalStateException: Should has at least one way to know which services this interface belongs to, subscription url: consumer://192.168.0.101/org.apache.dubbo.demo.DemoService?REGISTRY_CLUSTER=org.apache.dubbo.config.RegistryConfig&application=demo-consumer&category=providers,configurators,routers&check=true&dubbo=2.0.2&enable-auto-migration=true&enable.auto.migration=true&init=false&interface=org.apache.dubbo.demo.DemoService&mapping-type=metadata&mapping.type=metadata&metadata-type=remote&methods=sayHello,sayHelloAsync&pid=6886&qos.port=33333&side=consumer&sticky=false&timestamp=1615218681551
	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:176)
	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:101)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1827)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getObjectForBeanInstance(AbstractAutowireCapableBeanFactory.java:1265)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:207)
	at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1115)
	at org.apache.dubbo.demo.consumer.Application.main(Application.java:34)
Caused by: java.lang.IllegalStateException: Should has at least one way to know which services this interface belongs to, subscription url: consumer://192.168.0.101/org.apache.dubbo.demo.DemoService?REGISTRY_CLUSTER=org.apache.dubbo.config.RegistryConfig&application=demo-consumer&category=providers,configurators,routers&check=true&dubbo=2.0.2&enable-auto-migration=true&enable.auto.migration=true&init=false&interface=org.apache.dubbo.demo.DemoService&mapping-type=metadata&mapping.type=metadata&metadata-type=remote&methods=sayHello,sayHelloAsync&pid=6886&qos.port=33333&side=consumer&sticky=false&timestamp=1615218681551
	at org.apache.dubbo.registry.client.ServiceDiscoveryRegistry.doSubscribe(ServiceDiscoveryRegistry.java:268)
	at org.apache.dubbo.registry.client.ServiceDiscoveryRegistry.subscribe(ServiceDiscoveryRegistry.java:257)
	at org.apache.dubbo.registry.ListenerRegistryWrapper.subscribe(ListenerRegistryWrapper.java:105)
	at org.apache.dubbo.registry.integration.DynamicDirectory.subscribe(DynamicDirectory.java:151)
	at org.apache.dubbo.registry.integration.RegistryProtocol.doCreateInvoker(RegistryProtocol.java:498)
	at org.apache.dubbo.registry.integration.InterfaceCompatibleRegistryProtocol.getServiceDiscoveryInvoker(InterfaceCompatibleRegistryProtocol.java:65)
	at org.apache.dubbo.registry.client.migration.MigrationInvoker.refreshServiceDiscoveryInvoker(MigrationInvoker.java:291)
	at org.apache.dubbo.registry.client.migration.MigrationInvoker.migrateToServiceDiscoveryInvoker(MigrationInvoker.java:112)
	at org.apache.dubbo.registry.client.migration.MigrationRuleHandler.doMigrate(MigrationRuleHandler.java:60)
	at org.apache.dubbo.registry.client.migration.MigrationRuleListener.onRefer(MigrationRuleListener.java:103)
	at org.apache.dubbo.registry.integration.RegistryProtocol.interceptInvoker(RegistryProtocol.java:471)
	at org.apache.dubbo.registry.integration.RegistryProtocol.doRefer(RegistryProtocol.java:457)
	at org.apache.dubbo.registry.integration.RegistryProtocol.refer(RegistryProtocol.java:451)
	at org.apache.dubbo.rpc.protocol.ProtocolListenerWrapper.refer(ProtocolListenerWrapper.java:72)
	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper.refer(ProtocolFilterWrapper.java:81)
	at org.apache.dubbo.rpc.Protocol$Adaptive.refer(Protocol$Adaptive.java)
	at org.apache.dubbo.config.ReferenceConfig.createProxy(ReferenceConfig.java:367)
	at org.apache.dubbo.config.ReferenceConfig.init(ReferenceConfig.java:305)
	at org.apache.dubbo.config.ReferenceConfig.get(ReferenceConfig.java:204)
	at org.apache.dubbo.config.spring.ReferenceBean.getObject(ReferenceBean.java:68)
	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:169)
	... 7 more