Jay Leno has been granted conservatorship of his 77-year-old wifeMavisafter she was diagnosed with dementia. A judge made it official during a hearing on Tuesday in Los Angeles County Superior Court after Mavis’ attorney said she was “in agreement” with the deal, RadarOnline.com has learned. The legendary late-night icon, 73, got glowing reviews from the legal team, who ensured his wife of over 40 years has been “receiving excellent care with her husband, Mr. Leno.” The judge agreed, saying, “I think she’s in the least restrictive environment. I think she’s in very good care with Mr. Leno,” pe…