Remove Index Templates V2 feature flag (#56123)

This will be available in the next minor release, so this removes the feature flag prior to the
feature freeze date.

Relates to #53101

build.gradle

@@ -520,7 +520,6 @@ subprojects {
   pluginManager.withPlugin('elasticsearch.testclusters') {
     testClusters.all {
       if (org.elasticsearch.gradle.info.BuildParams.isSnapshotBuild() == false) {
-        systemProperty 'es.itv2_feature_enabled', 'true'
         systemProperty 'es.datastreams_feature_enabled', 'true'
       }
     }

docs/build.gradle

@@ -81,7 +81,6 @@ testClusters.integTest {
 
   // TODO: remove this once cname is prepended to transport.publish_address by default in 8.0
   systemProperty 'es.transport.cname_in_publish_address', 'true'
-  systemProperty 'es.itv2_feature_enabled', 'true'
 }
 
 // build the cluster with all plugins

server/build.gradle

@@ -338,7 +338,6 @@ task integTest(type: Test) {
 
   include '**/*IT.class'
   if (org.elasticsearch.gradle.info.BuildParams.isSnapshotBuild() == false) {
-    systemProperty 'es.itv2_feature_enabled', 'true'
     systemProperty 'es.datastreams_feature_enabled', 'true'
   }
 }

server/src/main/java/org/elasticsearch/action/ActionModule.java

@@ -394,20 +394,6 @@ public class ActionModule extends AbstractModule {
 
     private static final Logger logger = LogManager.getLogger(ActionModule.class);
 
-    private static final boolean ITV2_FEATURE_ENABLED;
-
-    static {
-        final String property = System.getProperty("es.itv2_feature_enabled");
-        if (Build.CURRENT.isSnapshot() || "true".equals(property)) {
-            ITV2_FEATURE_ENABLED = true;
-        } else if ("false".equals(property) || property == null) {
-            ITV2_FEATURE_ENABLED = false;
-        } else {
-            throw new IllegalArgumentException("expected es.itv2_feature_enabled to be unset, true, or false but was [" +
-                property + "]");
-        }
-    }
-
     private static final boolean DATASTREAMS_FEATURE_ENABLED;
 
     static {
@@ -550,15 +536,13 @@ public class ActionModule extends AbstractModule {
         actions.register(PutIndexTemplateAction.INSTANCE, TransportPutIndexTemplateAction.class);
         actions.register(GetIndexTemplatesAction.INSTANCE, TransportGetIndexTemplatesAction.class);
         actions.register(DeleteIndexTemplateAction.INSTANCE, TransportDeleteIndexTemplateAction.class);
-        if (ITV2_FEATURE_ENABLED) {
-            actions.register(PutComponentTemplateAction.INSTANCE, TransportPutComponentTemplateAction.class);
-            actions.register(GetComponentTemplateAction.INSTANCE, TransportGetComponentTemplateAction.class);
-            actions.register(DeleteComponentTemplateAction.INSTANCE, TransportDeleteComponentTemplateAction.class);
-            actions.register(PutIndexTemplateV2Action.INSTANCE, TransportPutIndexTemplateV2Action.class);
-            actions.register(GetIndexTemplateV2Action.INSTANCE, TransportGetIndexTemplateV2Action.class);
-            actions.register(DeleteIndexTemplateV2Action.INSTANCE, TransportDeleteIndexTemplateV2Action.class);
-            actions.register(SimulateIndexTemplateAction.INSTANCE, TransportSimulateIndexTemplateAction.class);
-        }
+        actions.register(PutComponentTemplateAction.INSTANCE, TransportPutComponentTemplateAction.class);
+        actions.register(GetComponentTemplateAction.INSTANCE, TransportGetComponentTemplateAction.class);
+        actions.register(DeleteComponentTemplateAction.INSTANCE, TransportDeleteComponentTemplateAction.class);
+        actions.register(PutIndexTemplateV2Action.INSTANCE, TransportPutIndexTemplateV2Action.class);
+        actions.register(GetIndexTemplateV2Action.INSTANCE, TransportGetIndexTemplateV2Action.class);
+        actions.register(DeleteIndexTemplateV2Action.INSTANCE, TransportDeleteIndexTemplateV2Action.class);
+        actions.register(SimulateIndexTemplateAction.INSTANCE, TransportSimulateIndexTemplateAction.class);
         actions.register(ValidateQueryAction.INSTANCE, TransportValidateQueryAction.class);
         actions.register(RefreshAction.INSTANCE, TransportRefreshAction.class);
         actions.register(FlushAction.INSTANCE, TransportFlushAction.class);
@@ -702,15 +686,13 @@ public class ActionModule extends AbstractModule {
         registerHandler.accept(new RestGetIndexTemplateAction());
         registerHandler.accept(new RestPutIndexTemplateAction());
         registerHandler.accept(new RestDeleteIndexTemplateAction());
-        if (ITV2_FEATURE_ENABLED) {
-            registerHandler.accept(new RestPutComponentTemplateAction());
-            registerHandler.accept(new RestGetComponentTemplateAction());
-            registerHandler.accept(new RestDeleteComponentTemplateAction());
-            registerHandler.accept(new RestPutIndexTemplateV2Action());
-            registerHandler.accept(new RestGetIndexTemplateV2Action());
-            registerHandler.accept(new RestDeleteIndexTemplateV2Action());
-            registerHandler.accept(new RestSimulateIndexTemplateAction());
-        }
+        registerHandler.accept(new RestPutComponentTemplateAction());
+        registerHandler.accept(new RestGetComponentTemplateAction());
+        registerHandler.accept(new RestDeleteComponentTemplateAction());
+        registerHandler.accept(new RestPutIndexTemplateV2Action());
+        registerHandler.accept(new RestGetIndexTemplateV2Action());
+        registerHandler.accept(new RestDeleteIndexTemplateV2Action());
+        registerHandler.accept(new RestSimulateIndexTemplateAction());
 
         registerHandler.accept(new RestPutMappingAction());
         registerHandler.accept(new RestGetMappingAction());