staff: Fix duplicate listing of seiyuu for chars with multiple releases
staff: Fix duplicate listing of seiyuu for chars with multiple releases

This unfortunately means I had to remove the order-by-character-role
feature. It's possible to get that back, but it's not quite as trivial.

morkt/vndb,morkt/vndb,christian-roggia/vndb,morkt/vndb,erengy/vndb,christian-roggia/vndb,erengy/vndb,christian-roggia/vndb,morkt/vndb,morkt/vndb,erengy/vndb