kde5: get focus on dialogs on open

Change-Id: Ia78a0a2d26159e46bc58557477723a366b8e677a
Reviewed-on: https://gerrit.libreoffice.org/60010
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

vcl/qt5/Qt5Frame.cxx

@@ -565,6 +565,7 @@ void Qt5Frame::ToTop(SalFrameToTop nFlags)
 
     if (isWindow() && !(nFlags & SalFrameToTop::GrabFocusOnly))
         pWidget->raise();
+    pWidget->setFocus();
     pWidget->activateWindow();
 }