Improve isRunning() implementation for OrchestrationMetadata

Currently, isRunning() relies on the name, instanceId, and runtimeStatus parsed from the OrchestrationState returned over gRPC to determine whether the orchestration is running, however, there is also an Exists field on OrchestrationState that should also be considered, as runtimeStatus is populated from an enum with a default value.

This may also affect the implementation of isCompleted() and/or isInstanceFound()

定位 OrchestrationMetadata 及其 isRunning()、isCompleted() 和 isInstanceFound() 入口点，然后跟踪 OrchestrationState 如何通过 gRPC 接收。检查当前如何处理 Exists 字段和默认 runtimeStatus，并添加或更新测试，使受影响的方法能够正确区分存在的 orchestration 和不存在的 orchestration。