fix(game-tracking): don't initialise if kafka isnt present

Author: ZakShearman

src/main/java/dev/emortal/minestom/gamesdk/MinestomGameServerImpl.java

@@ -101,12 +101,13 @@ static final class BuilderImpl implements Builder, Builder.EndStep {
                 gameManager.addGameStatusListener(new AgonesGameStatusListener(config, kubernetesModule.getSdk()));
             }
 
-            GameTracker gameTracker = new GameTracker(messaging, config);
-            gameManager.addGameStatusListener(gameTracker);
-
             if (messaging != null) {
+                GameTracker gameTracker = new GameTracker(messaging, config);
+                gameManager.addGameStatusListener(gameTracker);
+
                 new AgonesGameListener(gameManager, config, messaging);
             }
+
             MinecraftServer.getCommandManager().register(new GameSdkCommand(gameManager));
 
             return new MinestomGameServerImpl(gameManager);

src/main/java/dev/emortal/minestom/gamesdk/internal/GameTracker.java

@@ -23,7 +23,6 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;