Describe the bug
A clear and concise description of what the bug is.

[Wastewater structure_symbol], [wastewater structure_text], [maintenance event_wastewater structure_assoc] and [reach_text] are not imported.
I have carried out an import and export test of my productive data and created a table of the quantity structure. It is clear that the previously mentioned classes are not imported.

There seems to be a bug in the class [MaintenanceEvent_WastewaterConstructionAssoc] in particular. As a result, no maintenance events are visible in Teksi.

The flush nozzle class is also not exported.

To Reproduce
Exact steps to reproduce the behavior:

1. Import Data
2. These classes are missing in the Object Selection task
   

Expected behavior
A clear and concise description of what you expected to happen.

The data import should include all original tables

Screenshots / data
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Desktop (please complete the following information):

• TWW version
• QGIS Version
• OS

Additional context
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