By Jarrett Renshaw and Costas Pitas (Reuters) -Former hedge fund executive David McCormick conceded to wellness celebrity Mehmet Oz on Friday in the Republican primary race for a U.S. Senate seat in Pennsylvania, following a recount and securing another Donald Trump-endorsed candidate in a critical midterm election. Oz, who will square off against Democrat John Fetterman in the Nov. 8 midterm election to replace retiring Republican Senator Pat Toomey, won by a margin of 916 votes, according to Edison Research. The race is crucial to Republican hopes of regaining control of a Senate now narrowl…