Fix adding/removing categorized/alphabetic mode buttons in wxPropertyGridManager.

Modify wxPropertyGridManager::RecreateControls() to allow adding/removing categorized/alphabetic mode buttons to/from wxPG manager tool bar at any time (not only when creating the tool bar).
Modify wxPropertyGridManager::SetExtraStyle() to fully support manipulating these buttons via wxPG_EX_MODE_BUTTONS flag.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78149 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775