Fix thread pool configuration is invalid

[sadlay]

What is the purpose of the change

Fix #11524

issue:
Initiating RPC in the life cycle initialization phase of Spring Bean, that is, before ServiceBean#afterPropertiesSet, because configManager does not have any serviceConfig, and without publishing any provider, the DefaultApplicationDeployer#exportMetadataService() method is first triggered, resulting in org.apache.dubbo.metadata The .MetadataService metadata interface is exported first, and finally the url is passed and fixed in the ChannelHandler. After the service starts to receive the request, when obtaining the ExecutorService, the thread pool of the MetadataService is obtained through the url, not the thread pool configured by parameters such as dubbo.protocol.threads.

solve:
When the getExecutor(URL url) method obtains the thread pool, if it is the provider side and has a user-defined interface, the service thread pool will be used first to avoid using its own thread when the registered URL is org.apache.dubbo.metadata.MetadataService pool.

Brief changelog

Verifying this change

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