ABC News is sealing a deal with veteran CNN correspondent Kate Snow to cover the White House beat for “Good Morning America.”An agreement with Snow, CNN’s congressional reporter, is expected to be made official next week. In addition to covering the White House, Snow will substitute for ABC “World News Tonight” White House correspondent Terry Moran when Moran is away. “Kate is a first-rate journalist. We wish her great success and are grateful for her many contributions to CNN,” the cable news net said in a statement. Snow, who recently returned from maternity leave, had apparently been approached by other news nets, including NBC and ABC.