Disable touch on screen blank

On the phone we're lucky since we tear down touch when disabling the panel but that's not true in general so we should disable touch input when blanking the screen.

This is somewhat related to !110 (merged) since we want proper input mapping to not turn off the wrong device and also to https://github.com/swaywm/wlroots/pull/1875 where the change requested by upstream - that we need to inform the compositor - will be beneficial to figuring out the right point in time (seems more puzzle parts are coming together which is nice)