[Fix] Set datatype for passed input_tensor as well

aidge_export_cpp/export.py

@@ -79,6 +79,7 @@ def export(export_folder_name: str,
     if inputs_tensor is not None:
         if inputs_tensor.dtype() == aidge_core.dtype.int32:
             set_nodes_datatypes(model)      # Set datatype to int8 only
+            inputs_tensor.set_datatype(aidge_core.dtype.int8)
             model.save(f"graph_log/3_set_datatypes")
 
     # [aidge_cmp] Export feature maps tensors as json