Make a dialog with a notebook in the dialog sample resizeable

It helps demonstrating how the layout works and is consistent with the
other windows in the sample (which are frames and so are resizeable by
default).

Closes #18830.

samples/layout/layout.cpp

@@ -400,7 +400,9 @@ MyFlexSizerFrame::MyFlexSizerFrame(wxFrame* parent)
 // ----------------------------------------------------------------------------
 
 MyNotebookWithSizerDialog::MyNotebookWithSizerDialog(wxWindow *parent, const wxString &title)
-             : wxDialog(parent, wxID_ANY, wxString(title))
+             : wxDialog(parent, wxID_ANY, wxString(title),
+                        wxDefaultPosition, wxDefaultSize,
+                        wxDEFAULT_DIALOG_STYLE | wxRESIZE_BORDER)
 {
     // Begin with first hierarchy: a notebook at the top and
     // and OK button at the bottom.