Fix NPE

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

BauSystem_Main/src/de/steamwar/bausystem/features/tracer/record/TraceAutoHandler.java

@@ -63,8 +63,10 @@ public class TraceAutoHandler implements Listener {
 
         if (lastExplosion > 80) {
             RecordStateMachine.autoIdle();
-            task.cancel();
-            task = null;
+            if (task != null) {
+                task.cancel();
+                task = null;
+            }
         }
     }
 }