Deletion of consecutive d3+ vertices too close to each other

In some case where multiple d3+ vertices are next to each others topology will be destroyed. In deep-learning outputs hedges are narrow and regular enough to not cause those issues. But with threshold method polygons can be wider than dangle length value thus creating more complex intersections. This behavior seems to be caused by the fact that vertices associated edges are not updated when creating/deleting edges. As calls to QgsVertex.incomingEdges or QgsVertex.outgoingEdges still returns old edges ids that does not exists anymore and thus does not match the new edge id returned by QgsGraph.addEdge. For now a workaround is to create a new instance of the graph each time we correct a vertex. But for large graph, instanciation can take time thus this solution is not implemented yet. workaround_correct_d3_too_closes.py