Set human entity to null

v1_17_R1/src/main/java/net/citizensnpcs/nms/v1_17_R1/entity/HumanController.java

@@ -90,6 +90,7 @@ public class HumanController extends AbstractEntityController {
             npc.getSkinTracker().onRemoveNPC();
         }
         NMS.remove(entity);
+        super.setEntity(null);
         // Paper decided to break Spigot compatibility.
         // super.remove();
     }