[9.0] Remove feature flag check in BaseTransportInferenceAction and rely on Noop implementation (#121270) (#121640)

Author: timgrein

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/action/BaseTransportInferenceAction.java

@@ -55,7 +55,6 @@
 
 import static org.elasticsearch.core.Strings.format;
 import static org.elasticsearch.xpack.inference.InferencePlugin.INFERENCE_API_FEATURE;
-import static org.elasticsearch.xpack.inference.common.InferenceAPIClusterAwareRateLimitingFeature.INFERENCE_API_CLUSTER_AWARE_RATE_LIMITING_FEATURE_FLAG;
 import static org.elasticsearch.xpack.inference.telemetry.InferenceStats.modelAttributes;
 import static org.elasticsearch.xpack.inference.telemetry.InferenceStats.responseAttributes;
 
@@ -188,10 +187,6 @@ private void validateRequest(Request request, UnparsedModel unparsedModel) {
     }
 
     private NodeRoutingDecision determineRouting(String serviceName, Request request, UnparsedModel unparsedModel) {
-        if (INFERENCE_API_CLUSTER_AWARE_RATE_LIMITING_FEATURE_FLAG.isEnabled() == false) {
-            return NodeRoutingDecision.handleLocally();
-        }
-
         var modelTaskType = unparsedModel.taskType();
 
         // Rerouting not supported or request was already rerouted