HWR transparent FoF plane brightness

This brings HWR closer to the intended look of transparent FoF volumes in dark sectors, however, software is not able to accurately express transparent lit FoF volumes the way HWR can, so there is still inconsistency in the rendering.

The truth is, neither renderer is correct here; HWR also incorrectly assumes that color 255 is always transparent, so transparent FoF volumes with flats using that color index will be drawn incorrectly.