uitest: annotate slidesorter window

Change-Id: Ie8c0cf79b8b92908a001271934a81fa2a2d6e693
Reviewed-on: https://gerrit.libreoffice.org/29447Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

sd/source/ui/framework/factories/BasicViewFactory.cxx

@@ -404,6 +404,7 @@ std::shared_ptr<ViewShell> BasicViewFactory::CreateViewShell (
             &rWindow,
             pFrameView,
             bIsCenterPane);
+        pViewShell->GetContentWindow()->set_id("slidesorter");
     }
 
     return pViewShell;