Fix ItemDeleted() call in wxTreeListModel.

While it doesn't matter when exactly do we call it with the generic or GTK
native implementations, under OS X we must update the internal model first and
call this method afterwards because it refreshes the control contents
immediately and so was calling back to the model and getting the pointer to
the item about to be deleted, which resulted in a crash when this pointer was
dereferences later.

Closes #15575.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75044 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/treelist.cpp

@@ -716,8 +716,6 @@ void wxTreeListModel::DeleteItem(Node* item)
 
     Node* const parent = item->GetParent();
 
-    ItemDeleted(ToDVI(parent), ToDVI(item));
-
     Node* previous = parent->GetChild();
     if ( previous == item )
     {
@@ -739,6 +737,8 @@ void wxTreeListModel::DeleteItem(Node* item)
 
         previous->DeleteNext();
     }
+
+    ItemDeleted(ToDVI(parent), ToDVI(item));
 }
 
 void wxTreeListModel::DeleteAllItems()