Send wxEVT_DATAVIEW_ITEM_EDITING_DONE after cancelling too

Previously this event was not sent at all if editing the item was
cancelled, e.g. by pressing Esc.

Do send it now from the generic implementation and update the sample to
show this event.

See #17835.

samples/dataview/dataview.cpp

@@ -1227,7 +1227,11 @@ void MyFrame::OnEditingStarted( wxDataViewEvent &event )
 void MyFrame::OnEditingDone( wxDataViewEvent &event )
 {
     wxString title = m_music_model->GetTitle( event.GetItem() );
-    wxLogMessage( "wxEVT_DATAVIEW_ITEM_EDITING_DONE, Item: %s", title );
+    wxLogMessage("wxEVT_DATAVIEW_ITEM_EDITING_DONE, Item: %s, new value %s",
+                 title,
+                 event.IsEditCancelled()
+                    ? wxString("unavailable because editing was cancelled")
+                    : event.GetValue().GetString());
 }
 
 void MyFrame::OnExpanded( wxDataViewEvent &event )