Ignore decoration when updating focused window in PointerInput and TouchInput

Currently, it's possible to have the case where the pointer input device
handler or the touch input device handler thinks that there's a focused
window, but the corresponding focused surface in wayland seat is unset,
because the pointer hovers the server side decoration.

If the server side decoration is destroyed, the input device handler will
fail to update wayland seat's focused surface.

In order to make pointer input device handler and touch input device
handler code more intuitive, this change makes focusUpdate() functions
ignore the decoration.

BUG: 411884
BUG: 440380