Duplicating a blueprint interface asset results in duplicate GraphGuid

When a blueprint interface asset is duplicated in the Content browser, UEdGraph::GraphGuid will not be regenerated so the two graphs will end up sharing the same GUID. This causes problems for any code that relies on the GUID - such as the way that Anim Layer Interfaces are validated to ensure that they valid in UAnimationGraphSchema::ConformAnimLayersByGuid().

This issue was reported on this [Link Removed] which talks about the effect on Anim Layer Interfaces but the issue can also be replicated with Blueprint Interface assets.

1. Create a blueprint interface asset
2. Duplicate the asset in the content browser
3. While debugging check the value of UEdGraph::GraphGuid - these will be the same