Hotfix NPE

Signed-off-by: yoyosource <yoyosource@nidido.de>

BauSystem_Main/src/de/steamwar/bausystem/features/killchecker/KillcheckerVisualizer.java

@@ -369,7 +369,9 @@ public class KillcheckerVisualizer {
 
     public boolean hide(Player player) {
         outline.removePlayer(player);
+        if (areaPlayers.contains(player)) {
             inner.removePlayer(player);
+        }
         players.remove(player);
         areaPlayers.remove(player);
         bossBars.remove(player).removePlayer(player);