Every great party has a moment where you wish it would go on forever. That point where you look around the room and hope against all hope that it could just go on and that the obligations that tomorrow always brings might never arrive. But part of you knows they will. Brockhampton’s latest record feels like the sonic equivalent of that moment. Saturation III is the end of one era for this 14 man boyband, troupe that seems simultaneously assured of itself and its future, but also not quite ready to let go of that perfect moment before reality sets in.  There are few stories from…