wayland/touch-popup-release: Fixed popup disappearing after touch release

When releasing DnD originating from a popup, there's was a bug (#1681 (closed)) which prevented the user from closing that popup by clicking anywhere other than the parent window of that popup.

That bug is only produced from mouse events and the fixed applied to it introduces a new bug that closes any popup menu opened by touch as soon as touch event release happens thus making all popups completely unusable for touchscreens.

Fixes: 22362378 ("wayland: Track pressed mouse buttons for popup grabs through modifiers")

Closes: #3752 (closed)