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()

Localiza OrchestrationMetadata y sus puntos de entrada isRunning(), isCompleted() e isInstanceFound(), y luego sigue cómo se recibe OrchestrationState mediante gRPC. Comprueba cómo se gestionan actualmente el campo Exists y el runtimeStatus predeterminado, y añade o actualiza pruebas para que los métodos afectados distingan correctamente entre orquestaciones existentes y no existentes.