Blender Git Loki

Fix T74074: Strokes with timer events don't get pressure values

When processing a timer event WM_event_tablet_data returns 0 instead of
the last valid pressure value from the tablet. This always stores the
last pressure value and uses it in case a timer event is being
processed.

Reviewed By: brecht

Maniphest Tasks: T74074

Differential Revision: https://developer.blender.org/D6950