Fix NPE of InviteCommand

src/de/steamwar/misslewars/commands/InviteCommand.java

@@ -83,19 +83,12 @@ public class InviteCommand extends SWCommand {
 
     @ClassValidator(value = Player.class, local = true)
     public TypeValidator<Player> validator() {
-        return new TypeValidator<Player>() {
-            @Override
-            public boolean validate(CommandSender commandSender, Player player, MessageSender messageSender) {
+        return (commandSender, player, messageSender) -> {
             if (Config.isChallenge()) {
-                    messageSender.send("§cDieser Command ist deaktiviert.");
+                player.sendMessage("§cDieser Command ist deaktiviert.");
                 return false;
             }
             return true;
-            }
         };
     }
-
-    private void message(MWTeam mwTeam, String s) {
-        mwTeam.getPlayers().forEach(player -> player.sendMessage(s));
-    }
 }