set_dataformat() should adapt to the tensor dimensions

Context

The graph_view.set_dataforamt(<aidge_core.dformat>) function allows to set the dataformat accross the whole model.

Issue

The dformat is set to the one given as argument whereas sometimes it does not make sense and can lead to issues (for instance, while generating the memory layout for an export. Here is an example :

The dataformat of the ROI producer is set to NHWC whereas it has no dimension.