Copy-pasting asset subgraphs does not work

Steps to reproduce:

1. Download and import the attached "GTK-DuplicateAssetSubgraph.unitypackage"
2. Open "New Graph"
3. Select the "Asset Subgraph" node
4. Copy and paste it or duplicate it

Actual results: The asset subgraph node is not duplicated

Expected results: The asset subgraph node is duplicated

Tested on (OS): MacOS

Notes:

• Duplicating local subgraphs works as expected