sprites: reduce height of cyberdemon corpse
sprites: reduce height of cyberdemon corpse

Lowered head of final frame of cyberdemon's death sequence to ground,
so it won't block vision.

Signed-off-by: RjY <83893d85028dba5ed7fb8142c08f77f1480bf584@users.sourceforge.net>

CWolfRU/freedoom,jmtd/freedoom,jmtd/freedoom,jmtd/freedoom,CWolfRU/freedoom