Prevent NPE when setting tempt target to null

nms-patches/PathfinderGoalTempt.patch

@@ -34,7 +34,7 @@
 +                if (event.isCancelled()) {
 +                    return false;
 +                }
-+                this.target = ((CraftLivingEntity) event.getTarget()).getHandle();
++                this.target = (event.getTarget() == null) ? null : ((CraftLivingEntity) event.getTarget()).getHandle();
 +            }
 +            return tempt;
 +            // CraftBukkit end