Keeping busy! Less than two months after losing mom Lisa Marie Presley, Riley Keough was back in the spotlight, promoting her new Amazon show, Daisy Jones & The Six. “She’s still heartbroken, but she’s putting on a brave face,” says a source. “Interviewers aren’t asking her about Lisa Marie, as requested by Riley’s team, which makes it easier.” Another reason for avoiding the topic? The actress, 33, is currently battling it out with Priscilla Presley over the late Lisa Marie’s $35 million estate. Shortly after the singer, 54, was laid to rest at Graceland in January, Elvis’ ex, 77, discovered that her daughter’s will had been amended in 2016, removing Priscilla and former business manager Barry Siegel as co-trustees and replacing them with Lisa Marie’s eldest children, Riley and Benjamin…