fix queueevent message attempting to be send when the player is not connected

common/src/main/java/us/ajg0702/queue/common/QueueManagerImpl.java

@@ -433,6 +433,7 @@ public class QueueManagerImpl implements QueueManager {
             for (QueuePlayer queuePlayer : s.getQueue()) {
                 AdaptedPlayer player =  queuePlayer.getPlayer();
                 if (player == null || !player.isConnected()) continue;
+                if(player.getServerName() == null) continue;
                 main.getPlatformMethods().sendPluginMessage(player, "inqueueevent", "true");
             }
         }