Skip downsample IT test with TS command when command not present (#131556)

Fixes #131500

Author: limotova

muted-tests.yml

@@ -475,9 +475,6 @@ tests:
 - class: org.elasticsearch.xpack.search.CrossClusterAsyncSearchIT
   method: testCancellationViaTimeoutWithAllowPartialResultsSetToFalse
   issue: https://github.com/elastic/elasticsearch/issues/131248
-- class: org.elasticsearch.xpack.downsample.DownsampleIT
-  method: testAggMetricInEsqlTSAfterDownsampling
-  issue: https://github.com/elastic/elasticsearch/issues/131500
 - class: org.elasticsearch.xpack.esql.qa.multi_node.GenerativeIT
   method: test
   issue: https://github.com/elastic/elasticsearch/issues/131508

x-pack/plugin/downsample/src/internalClusterTest/java/org/elasticsearch/xpack/downsample/DownsampleIT.java

@@ -7,7 +7,7 @@
 
 package org.elasticsearch.xpack.downsample;
 
-import org.elasticsearch.Build;
+import org.elasticsearch.action.admin.cluster.node.capabilities.NodesCapabilitiesRequest;
 import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
 import org.elasticsearch.action.admin.indices.delete.TransportDeleteIndexAction;
 import org.elasticsearch.action.admin.indices.rollover.RolloverRequest;
@@ -18,6 +18,7 @@
 import org.elasticsearch.cluster.metadata.DataStreamAction;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.search.aggregations.bucket.histogram.DateHistogramInterval;
 import org.elasticsearch.test.ClusterServiceUtils;
 import org.elasticsearch.xcontent.XContentBuilder;
@@ -35,6 +36,7 @@
 
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.xpack.downsample.DownsampleDataStreamTests.TIMEOUT;
+import static org.elasticsearch.xpack.esql.action.EsqlCapabilities.Cap.METRICS_COMMAND;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasSize;
 
@@ -216,9 +218,11 @@ public void testAggMetricInEsqlTSAfterDownsampling() throws Exception {
         };
         bulkIndex(dataStreamName, nextSourceSupplier, 100);
 
-        if (Build.current().isSnapshot() == false) {
-            return;
-        }
+        // check that TS command is available
+        var response = clusterAdmin().nodesCapabilities(
+            new NodesCapabilitiesRequest().method(RestRequest.Method.POST).path("/_query").capabilities(METRICS_COMMAND.capabilityName())
+        ).actionGet();
+        assumeTrue("TS command must be available for this test", response.isSupported().orElse(Boolean.FALSE));
 
         // Since the downsampled field (cpu) is downsampled in one index and not in the other, we want to confirm
         // first that the field is unsupported and has 2 original types - double and aggregate_metric_double