Fixed useless group query

kafka-ui-api/src/main/java/com/provectus/kafka/ui/cluster/service/ClusterService.java

@@ -70,15 +70,10 @@ public class ClusterService {
     public Mono<ResponseEntity<ConsumerGroupDetails>> getConsumerGroupDetail(String clusterName, String consumerGroupId) {
         KafkaCluster cluster = clustersStorage.getClusterByName(clusterName);
 
-        return ClusterUtil.toMono(cluster.getAdminClient().listConsumerGroups().all())
-                .flatMap(groups ->
-                        ClusterUtil.toMono(
-                                cluster.getAdminClient()
-                                        .describeConsumerGroups(groups.stream().map(ConsumerGroupListing::groupId).collect(Collectors.toList()))
-                                        .all()
-                        )
-                )
-                .flatMap(groups ->
+        return ClusterUtil.toMono(
+                        cluster.getAdminClient()
+                                .describeConsumerGroups(Collections.singletonList(consumerGroupId)).all()
+                ).flatMap(groups ->
                         groupMetadata(cluster, consumerGroupId).map(
                             offsets -> {
                                 Map<TopicPartition, Long> endOffsets = topicPartitionsEndOffsets(cluster, offsets.keySet());