Fix brushes being able to get drawn outside of the selection, if the selection is outside the canvas

Author: OverloadedOrama

src/Tools/Draw.gd

@@ -432,7 +432,7 @@ func remove_unselected_parts_of_brush(brush: Image, dst: Vector2) -> Image:
 	for x in size.x:
 		for y in size.y:
 			var pos := Vector2(x, y) + dst
-			if !project.selection_map.is_pixel_selected(pos):
+			if !project.can_pixel_get_drawn(pos):
 				new_brush.set_pixel(x, y, Color(0))
 	new_brush.unlock()
 	return new_brush