With movie theaters closed, the cutthroat competition for Christmas 2020 viewers is focused on streaming. Last year Netflix dominated the holidays at home with the big-budget, high-profile fantasy “The Witcher.” This time, the champ is back with a whole new type of fantasy series with an adaptation of the Regency romance series of novels known as “Bridgerton.” ........................................................ “Bridgerton” features none of these fig leaves. The series is the second Netflix title from Shonda Rhimes, best known for steamy ABC shows like “Grey’s Anatomy,” “Scandal,” and “How To Get Away With Murder.” Here, she unapologetically serves up joyous sentimentality and...