`TransportGetShutdownStatusAction` has a few checks that prevents the node from being shut down if there are shards without a copy that we can't move. We should also check that whether the node has unassigned shard and if it does, return the `STALLED` status and prevent the node from being shut down.

Relates #73873, #78578
x-pack/plugin/shutdown/src/main/java/org/elasticsearch/xpack/shutdown/TransportGetShutdownStatusAction.java
import org.elasticsearch.cluster.metadata.ShutdownShardMigrationStatus;
import org.elasticsearch.cluster.metadata.SingleNodeShutdownMetadata;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.ShardRoutingState;
import org.elasticsearch.cluster.routing.allocation.AllocationDecision;
import org.elasticsearch.cluster.routing.allocation.AllocationService;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
import org.elasticsearch.cluster.routing.allocation.ShardAllocationDecision;
import org.elasticsearch.cluster.routing.allocation.decider.AllocationDeciders;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.core.Tuple;
import org.elasticsearch.shutdown.PluginShutdownService;
import org.elasticsearch.snapshots.SnapshotsInfoService;
import org.elasticsearch.tasks.Task;
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.transport.TransportService;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
import static org.elasticsearch.cluster.metadata.ShutdownShardMigrationStatus.NODE_ALLOCATION_DECISION_KEY;
import static org.elasticsearch.core.Strings.format;
public class TransportGetShutdownStatusAction extends TransportMasterNodeAction<