Use list mode in wxListbook list control instead of report.

Use wxLC_LIST instead of wxLC_REPORT when we don't have any icons. This makes
the code simpler as wxLC_LIST is more similar to wxLC_ICON which we used, and
continue to use, when we do have icons, because we don't need to add and
remove any columns on the fly.

And it fixes the appearance of wxListbook without images with wxBK_TOP or
wxBK_BOTTOM styles as it now lays out its items horizontally and not
vertically as before.

It also fixes the best size calculation of wxListbook control since the
changes to wxListCtrl best size calculations in r71733 as a nice side effect.

Closes #14451.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71965 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/listbook.h

@@ -88,10 +88,6 @@ protected:
     wxBookCtrlEvent* CreatePageChangingEvent() const;
     void MakeChangedEvent(wxBookCtrlEvent &event);
 
-    // get flags for different list control modes
-    long GetListCtrlIconViewFlags() const;
-    long GetListCtrlReportViewFlags() const;
-
     // event handlers
     void OnListSelected(wxListEvent& event);
     void OnSize(wxSizeEvent& event);