Flex ****
By: David Sheward July 23,2023: You don't need a working knowledge of basketball to enjoy Flex, Candrice Jones's infectious and fast-paced new play on friendship and competition in a high-school girls team at Lincoln Center's Off-Broadway Mitzi E. Newhouse Theater, but it would help. There is a lot of talk about point guards, fouling, and free throws but the more important themes involve the limits and responsibil…