Ensure that client display rectangle is always less than its total area.

Ensure that client display rectangle is always less than its total area.

Under Unix we could return client display rectangle that was bigger than the
entire display size as it corresponded to the total screen size when
_NET_WORKAREA was not supported or was not correctly implemented by the WM.

Fix this by explicitly intersecting the client rect with the total one.

Closes #14419.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73282 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775