Do not actually reconnect PG event handlers when attempting to reconnect them to the same window.

When in wxPropertyGridManager::ReconnectEventHandlers() new window ID is the same as old window ID then there is no need to do anything with handlers. An assertion warning is displayed in this case to notify about this unusual (and maybe unintended) situation.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78321 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775