Will Thorne Staff Writer“Succession” has added another intriguing piece to the Season 3 puzzle.Swiss actor Ella Rumpf, best known for her leading role in Julia Ducournau’s fleshy horror pic “Raw,” is set to play a guest starring role in the HBO drama’s upcoming third outing, Variety has learned exclusively.Although the exact nature of her role is being kept under wraps, sources say Rumpf already finished shooting the part in Italy, where Season 3 production has been ongoing since June.A role in