Update the associated grad tensor when tensor is resized

Context

Fix tests failure after integration of !397

Detailed modifications

Call forward_dims() before setGrad() is called

enabled an automatic merge when all merge checks for 7d8a52b4 pass

assigned to @oantoni

requested review from @olivierbichler

approved this merge request

merged

changed milestone to %aidge v0.6.0

added Fix 🔥🔥 Unit-test 🧪 labels