[QUESTION] - MicroserviceInstanceStatus 不再支持 OUTOFSERVICE

### Steps to reproduce (if applicable)

org.apache.servicecomb.service.center.client.model.MicroserviceInstanceStatus 还有 OUTOFSERVICE状态，org.apache.servicecomb.registry.api.MicroserviceInstanceStatus 去除了 OUTOFSERVICE；
是出于什么考虑呢？

在本地调测过程中用的还比较多，DOWN状态是否可以完全替代 OUTOFSERVICE

### What have you tried so far?

_No response_

### Additional context

_No response_

Compare org.apache.servicecomb.service.center.client.model.MicroserviceInstanceStatus with org.apache.servicecomb.registry.api.MicroserviceInstanceStatus and trace where OUTOFSERVICE and DOWN are consumed. Clarify the intended status lifecycle with maintainers; done means an agreed compatibility or replacement behavior, backed by any relevant tests identified during that review.

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