Fix T52321: Draw Poly Brush allow Grease Pencil right click

Bumped version to 0.3.8
Allow passing of the Right Click to bpy.ops.gpencil.draw
as it is used for the eraser functionality
Add a message about user abort

Temporary switch on the continuous drawing for GP
as if it is False will stop as right click is pressed

Correct the tooltip, so it is more clear