Blender Git Loki

Fix macOS mouse positions inaccuracy

Don't use the current mouse position at the time the event is handled, but
rather the position at the time of the event. This should make e.g. brush
stroke paths more accurate.

In addition, this may solve issues with other software that does mouse
position smoothing. Ref T82143.

Use of the current mouse position was added in 12b642062c6f as part of a
large commit that also made continuous grab work. But it appears to still
work getting the mouse position from the event.