Missing sub type definition in exported files (marked with green plus in GUI)

Requirement concerned:

As a User, I need subtypes like BACnetYear to be included in the exported files, to ensure that the application software can be compiled successfully.

Description:

In the OPC UA structure BACnetCalendarEntry, the companion specification adds a subtype BACnetYear. This addition is visually indicated by a green plus icon. However, there is a bug where the definition for BACnetYear is missing in the exported files. This inconsistency leads to potential confusion and errors in using the exported data. (see screenshot-1.png and see Example_OPCUA_MQTT_subtypeWithPlus_butNotInExportedFileds.zip)

Current Workaround: Manually add the subtype BACnetYear using the "Add to Address Space" option and re-export the files. Following this procedure, the subtype appears correctly in the exported files.

Steps to reproduce:

1. Open the OPC UA structure Enumeration->BACnetYear and observe the green plus icon indicating the addition.
2. Export the files from the OPC UA structure.
3. Review the exported files and note the absence of the BACnetYear definition.
4. Apply the workaround by manually adding BACnetYear using "Add to Address Space" and re-export the files.
5. Confirm that the BACnetYear subtype is now present in the newly exported files.