Fix selection in virtual generic wxDataViewCtrl after deleting items.

The number of items managed by selection was first decremented by our own
UpdateCount() and then, again, by an explicit call to wxSelectionStore::
OnItemDelete(), which resulted in the selection ending up in an invalid state.

Fix this by not calling UpdateCount(), and hence wxSelectionStore::
SetItemCount(), at all, just OnItemDelete() is enough.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78363 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/datavgen.cpp

@@ -2385,7 +2385,7 @@ bool wxDataViewMainWindow::ItemDeleted(const wxDataViewItem& parent,
     {
         wxDataViewVirtualListModel *list_model =
             (wxDataViewVirtualListModel*) GetModel();
-        UpdateCount(list_model->GetCount());
+        m_count = list_model->GetCount();
 
         m_selection.OnItemDelete(GetRowByItem(item));
     }