Add missing color argument in forward_canvas_draw_over_viewport example.
Add missing color argument in forward_canvas_draw_over_viewport example.

(cherry picked from commit 034c48dbeddbd88e88a2b3e45a2eb06ecf90bd81)

ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot