fix: custom node example not fitting view

* fit view can't work (for the onLoad event) for elements assigned after the host has mounted (onMounted hook) as we can't calculate a rect of elements that don't exist at flow creation
* in this case just trigger fit view __after__ elements have been created/passed to the flow

Signed-off-by: Braks <78412429+bcakmakoglu@users.noreply.github.com>

docs/pages/examples/layouting.vue

@@ -27,7 +27,6 @@ const elements = ref<Elements>(initialElements)
 const onConnect = (params: Connection | Edge) => (elements.value = addEdge({ ...params, animated: true }, elements.value))
 const onElementsRemove = (elementsToRemove: Elements) => (elements.value = removeElements(elementsToRemove, elements.value))
 
-// todo changing elements not properly updating flowchart...
 const onLayout = (direction: string) => {
   const isHorizontal = direction === 'LR'
   dagreGraph.setGraph({ rankdir: direction })