vtws_revise fails because of undefined function Inventory_TaxRecord_Model::getSelectedDefaultTaxMode()

See https://code.vtiger.com/vtiger/vtigercrm/blob/master/include/Webservices/LineItem/VtigerInventoryOperation.php#L228

The function Inventory_TaxRecord_Model::getSelectedDefaultTaxMode() is not defined anywhere in Vtiger. Maybe it was removed at some point.

I noticed the error when trying to use vtws_revise to edit a field of an Invoice record.