Improve MRT handling

Author: smalyshev

server/src/main/java/org/elasticsearch/action/admin/cluster/stats/CCSUsageTelemetry.java

@@ -159,7 +159,11 @@ private void doUpdate(CCSUsage ccsUsage) {
             skippedRemotes.increment();
             ccsUsage.getSkippedRemotes().forEach(remote -> byRemoteCluster.computeIfAbsent(remote, PerClusterCCSTelemetry::new).skipped());
         }
-        ccsUsage.getFeatures().forEach(f -> featureCounts.computeIfAbsent(f, k -> new LongAdder()).increment());
+        ccsUsage.getFeatures().forEach(f -> {
+            if (useMRT || f.equals(MRT_FEATURE) == false) {
+                featureCounts.computeIfAbsent(f, k -> new LongAdder()).increment();
+            }
+        });
         String client = ccsUsage.getClient();
         if (client != null && KNOWN_CLIENTS.contains(client)) {
             // We count only known clients for now

server/src/test/java/org/elasticsearch/action/admin/cluster/stats/CCSUsageTelemetryTests.java

@@ -358,5 +358,6 @@ public void testUseMRTFalse() {
         assertThat(snapshot.getTook().count(), equalTo(2L));
         assertThat(snapshot.getTookMrtFalse().count(), equalTo(0L));
         assertThat(snapshot.getTookMrtTrue().count(), equalTo(0L));
+        assertThat(snapshot.getFeatureCounts().size(), equalTo(0));
     }
 }