Bug： Addons are removed after customized owner node's UFlowGraphNode

[tcmxx]

• How to Reproduce the bug:

Create a flow asset with a any node（node without custom UFlowGraphNode） in it. Add a couple of addons to the node.

Save the flow graph and close UE editor.

Now, add a custom UFlowGraphNode to customize the node's graph node(similar to UFlowGraphNode_Branch).

Then compile and reopen UE, and open the flow asset just created.

You will find the addons are all removed from previous node.

• Cause
  Seems like UFlowGraph::RefreshGraph() will recreate the node when UFlowGraphNode changed, but then its addons graphnode will not be recreated and added to the new node's graph node.

One way to fix it is to force recreate addon's GraphNode when the owning node graphnode is recreated.