Walk mode implemented it's own grab which relied on WM_cursor_warp
to work (which isn't implemented for wayland).
Resolve this by using WM_cursor_grab_{enable/disable}.
Besides fixing Wayland this removes the need for workarounds:
- Ensure the event received were after the event generated from warping.
- Alternate logic that reset the "center" when using tablets.
- Checking the cursor location was scaled by native-pixels on macOS.
There is a minor change in behavior: on completion the cursor is left
at the location walk-mode began instead of the center of the region.
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