PARIS—Unseeded Karolina Muchova reached her first Grand Slam final at the last place she expected, saving a match point and using a stirring comeback to grab the last five games despite dealing with leg problems for a 7-6 (5), 6-7 (5), 7-5 victory over No. 2 Aryna Sabalenka at the French Open on Thursday. Sabalenka,…