[Backport to xwayland-23.2] xwayland: Send ei_device_frame on device_scroll_discrete
This fixes the scroll action in Steam Input in SteamOS/Gamescope when using the new libeis backend.
Fixes: a1333342 ("xwayland: Add XTEST support using EIS") Signed-off-by: Joshua Ashton joshua@froggi.es Part-of: !1531 (merged) (cherry picked from commit 7745fde2)