This PR replaces all pointer events on X11 with their XI2 equivalents,
which fixes problems with scroll events not being reported when a mouse
button is down. Additionally it closes #11206 by resetting the tracked
global scroll valulator position with `None` on a leave event to prevent
a large scroll delta if scrolling is done outside the window. Lastly, it
resolves the bad window issue kvark was having.

Release Notes:

- Fixed X11 Scroll snapping (#11206 ).

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Co-authored-by: Mikayla Maki <mikayla@zed.dev>