Generating a NeTEx export fails when stops have fare zones

[culka]

When creating an export with stops using only fare zones and no tariff zones the export process stops and throws the following exception:

---         |(?)| An I/O error has occurred while writing a response message entity to the container output stream.
org.glassfish.jersey.server.internal.process.MappableException: java.lang.RuntimeException: jakarta.xml.bind.MarshalException
 - with linked exception:
[org.xml.sax.SAXParseException; lineNumber: 0; columnNumber: 0; cvc-complex-type.2.4.b: The content of element 'tariffZones' is not complete. One of '{"http://www.netex.org.uk/netex":TariffZoneRef}' is expected.]

This seems to be caused by the logic trying to use tariff zones instead of fare zones.