Hydraulic structure: fix crashing bug happening when we select the section combobox without selecting a reach in the first combobox

src/View/HydraulicStructures/Table.py

@@ -96,6 +96,9 @@ class ComboBoxDelegate(QItemDelegate):
             reach = self._data.hydraulic_structures\
                               .get_for_enabled_reaches(index.row())\
                               .input_reach
+            if reach is None:
+                value = None
+            else:
                 profiles = list(
                     filter(
                         lambda p: p.display_name() == text,