By Philip Pullella VATICAN CITY (Reuters) -Pope Francis condemned the cruelty of the war in Ukraine on Saturday at an Easter vigil Mass he attended but at which he did not preside, presumably because of leg pain that has forced him to curtail activities. The Mass was attended by Ivan Fedorov, the mayor of Melitopol, who was detained by Russian forces last month and later freed in a prisoner exchange. Italian Cardinal Giovanni Battista Re replaced the pope as the main celebrant at the service, which involved a procession in near-total darkness up the central nave of Christendom’s largest church…