[BUG] random_configuration_model never halt when degree sequence is not graphic

[etiennedeg]

random_configuration_model(3, [2, 0, 0]) never halt.

This is because our implementation of the random configuration model does not allow self loops and multi-edges. In itself, it is already an oddity because it does not respect the uniformity of sampling, but if we keep it this way, we should check that the degree sequence provided is graphic.