Avoid NPE on featureDiscovery creation (#9353)

* Avoid NPE on featureDiscovery creation

* Review

Author: amarziali

communication/src/main/java/datadog/communication/ddagent/SharedCommunicationObjects.java

@@ -142,7 +142,7 @@ public DDAgentFeaturesDiscovery featuresDiscovery(Config config) {
     DDAgentFeaturesDiscovery ret = featuresDiscovery;
     if (ret == null) {
       synchronized (this) {
-        if (featuresDiscovery == null) {
+        if ((ret = featuresDiscovery) == null) {
           createRemaining(config);
           ret =
               new DDAgentFeaturesDiscovery(