fix lighting bug when adding mesh

src/babylon.scene.ts

@@ -2221,6 +2221,7 @@
             if (this.collisionCoordinator) {
                 this.collisionCoordinator.onMeshAdded(newMesh);
             }
+            newMesh._resyncLightSources();
 
             this.onNewMeshAddedObservable.notifyObservers(newMesh);
         }