By Tim Kenneally LOS ANGELES (TheWrap.com) – Valerie Harper, who earlier this year announced that she’d been diagnosed with terminal brain cancer, has signed on for the upcoming season of “Dancing With the Stars,” TMZ reports. The former “Rhoda” star, 74, revealed her diagnosis in March, saying doctors had given her as little as three months to live. That period has passed, and Harper signed on in late July to star in the television film “The Town That Came A-Courtin” opposite Lauren Holly. That project will air on the cable network UP in January. …