scene: ensure OpenGL texture is updated after direct scanout

While direct scanout happens, the damage of the SurfaceItem is reset, which can cause the OpenGL texture to not be updated once direct scanout ends, and leave the texture outdated until the surface is damaged again. In order to fix that, make sure the texture is always fully updated after the SurfaceItem has been used in direct scanout.

@nicolasfella iirc you've seen this problem happen before