fix: don't update kill statistics if player died of own account (#242)

Co-authored-by: Josephine Rueckert <jd.rueckert@googlemail.com>

src/main/java/org/terasology/module/lightandshadow/systems/PlayerDeathSystem.java

@@ -61,7 +61,10 @@ public void beforeDestroy(BeforeDestroyEvent event, EntityRef player,
         if (player.hasComponent(PlayerCharacterComponent.class)) {
             event.consume();
             String team = player.getComponent(LASTeamComponent.class).team;
-            updateStatistics(event.getInstigator(), "kills");
+            // if a player dies on their own account, we don't want to update kill statistics
+            if (event.getInstigator() != EntityRef.NULL) {
+                updateStatistics(event.getInstigator(), "kills");
+            }
             updateStatistics(player, "deaths");
             dropItemsFromInventory(player);
             player.send(new RestoreFullHealthEvent(player));