WinInk: Simulate native mouse events for handled pen events

The code now simulates native mouse events with SetCursorPos and
SendInput for pen pointer events whose QTabletEvents are handled by
the widgets, so that the cursor position is updated to get correct
results from QCursor::pos().

BUG: 386475
BUG: 386476
Differential Revision: https://phabricator.kde.org/D8801