This week "Sunday Morning," hosted by Jane Pauley, features Jim Axelrod's story of high school junior Alexandra Valoras, who kept her personal despair hidden from everyone until ending her life. Plus: Lee Cowan talks with Delia Owens, author of the bestselling novel "Where the Crawdads Sing"; Anthony Mason checks out designer Thomas Heatherwick's extraordinary new public art project, a 150-foot-tall staircase in New York City's Hudson Yards; Tracy Smith talks with Julia Louis-Dreyfus and the cast of "Veep" as the HBO comedy enters its seventh and final season; and Martha Teichner goes inside America's Test Kitchen.