Prince Harry branded Prince William his “arch-nemesis” in his hotly-anticipated bombshell memoir, “Spare.” The Duke of Sussex’s harsh words were quoted by Good Morning America anchor Michael Strahan in a teaser for his one-on-one interview with Harry. “There’s a quote in the book where you refer to your brother as your ‘beloved brother and arch-nemesis,'” Strahan tells the duke. “Strong words. What did you mean by that?” “There has always been this competition between us, weirdly,” Harry responds. “I think it really plays into — or is played by — the ‘heir, spare.'” The full interview is set to air...