QtCompositor: When forwarding touch events to clients, mouse events are not working reliable anymore in the compositor UI

Attached example is based on the pure-qml compositor and extends it, by adding a button to the background and set touchEventsEnabled to true for the connected shell surfaces.

When multiflame.qml is used as a client, the touch events are forwarded and it works as expected, but aftwards when pressing the "green" button in the compositor api, will change to "red' to indicate that it is pressed, but never changes back to "green"

1. Launch modified compositor
2. Test that green button works as expected (changes to red)
3. launch multiflame as a wayland client
4. Do a two finger press (fast) in the multiflame window and verify that it renders two flames.
5. Press the green button again and see that's it's still red after releasing the finger