`epo:hasProcedureType` should not be mandatory, as it creates data validation problems

[csnyulas]

ePO declares the epo:hasProcedureType property that links the epo:Porcedure to the at-voc:procurement-procedure-type vocabulary as mandatory (multiplicity is set to 1):

However, in the eForms notices, the field that represents this property, BT-105-Procedure (defined here) is based on the Business Term BT-105, which according to the eForms Annex Table 2 depending on the eForms notice subtypes can be mandatory (M), optional (O), or not allowed:

So, certain valid eForm notices, such as 673305-2023 or 50012-2024 of subtype 12, or 735069-2023 of subtype 14, or even the SDK example notice cn_23.xml of subtype 19, when transformed to RDF will raise SHACL violations, as they will not have a value for the epo:hasProcedureType property.

This problems could be solved if the multiplicity of the epo:hasProcedureType would be relaxed to 0..1.