oda:DataProduct output has no type_key required for output

[ferrigno]

A line as this one in the outputs-tagged cell
rmf = jemx_rmf_dp # oda:DataProduct ; oda:label "RMF file"
causes the error

File /opt/conda/lib/python3.10/site-packages/nb2workflow/nbadapter.py:1183, in validate_oda_dispatcher(nba, optional, machine_readable)
   1179 prod_list = nbpq.build_product_list(instrument=None, res=MockRes, out_dir=None)
   1181 for prod in prod_list:
   1182     logger.info("\033[33mworkflow the output produces ODA product \033[0m: \033[31m%s\033[0m (%s) %s", 
-> 1183                 prod.name, prod.type_key, prod)
   1185 if machine_readable:
   1186     print("WORKFLOW-DISPATCHER-SIGNATURE:", json.dumps([
   1187                 {"parameters": dispatcher_parameters,
   1188                  "outputs": [{'name': prod.name, 'type': prod.type_key, 'class_name': prod.__class__.__name__} for prod in prod_list]
   1189                 }]))

AttributeError: 'NB2WProduct' object has no attribute 'type_key'

This is because the class
class NB2WProduct: (line 39 of products.py) has no attribute type_key which is defined only for the derived classes.

As the NB2WProduct constructor is valid only for NumpyDataProduct-based products, I propose the associated PR