Links created through the normal Python API are invalid since
7026096099. Before then, one could create links to or from virtual
sockets from Python (grayed out sockets in Group Input and Group
Output nodes), as is still possible in the GUI.
This is documented as an API change, and it broke at least Node
Wrangler, see blender/blender-addons#104470. Instead of just fixing
that, let's introduce an API to make this operation simpler.
Pull Request: https://projects.blender.org/blender/blender/pulls/105975
81815681d0