ZUGFeRDImporter: Fix index out of range error

Jobs/EDMI/ZUGFeRD/ImportZUGFeRDFiles.vb

@@ -345,9 +345,11 @@ Public Class ImportZUGFeRDFiles
                                         For Each oColumn As KeyValuePair(Of XmlItemProperty, List(Of Object)) In oPropertyList
                                             Dim oTableName As String = oColumn.Key.TableName
                                             Dim oPropertyDescription As String = oColumn.Key.Description
-                                            Dim oPropertyValue = oColumn.Value.Item(oRowIndex)
                                             Dim oRowCounter = oRowIndex + oGlobalGroupCounter + 1
 
+                                            ' Returns nothing if oColumn.Value contains an empty list
+                                            Dim oPropertyValue = oColumn.Value.ElementAtOrDefault(oRowIndex)
+
                                             _logger.Debug("Processing property {0}.", oPropertyDescription)
 
                                             If IsNothing(oPropertyValue) OrElse String.IsNullOrEmpty(oPropertyValue) Then