Fix missing selection event in generic wxDataViewCtrl

No event was sent if the selection was narrowed by clicking on an
already selected item without any key modifiers pressed.

Fix this by generating an event always on click and not only when
selecting a new item.

Closes #17881.

src/generic/datavgen.cpp

@@ -4728,9 +4728,9 @@ void wxDataViewMainWindow::OnMouse( wxMouseEvent &event )
             if ( UnselectAllRows(m_lineSelectSingleOnUp) )
             {
                 SelectRow( m_lineSelectSingleOnUp, true );
-                SendSelectionChangedEvent( GetItemByRow(m_lineSelectSingleOnUp) );
             }
-            //else: it was already selected, nothing to do
+
+            SendSelectionChangedEvent( GetItemByRow(m_lineSelectSingleOnUp) );
         }
 
         // If the user click the expander, we do not do editing even if the column