Nope there have only been 2 ex cathedra dogmas.  You are simply incorrect.  That does not mean we don't treat some of those beliefs with equal confidence as true.  However, that definitely does not include. . . that Christ ordained the 12 Apostles at the Last Supper is a de fide teaching of the Church. No-sorry-We assume that Jesus picked the 12 to lead our church as priests but Christ and even the apostles themselves tell us that the priesthood is the same royal priesthood all the followers are equally a part of and the Church does not state this is an official ordination of only the Apostles in fact it can't be because this meal did not just include the apostles or no gospel indicates that. The last supper was a Seder meal, that symbolically had to include male and female family and even friends per the directions for Passover stated clearly in Exodus by Moses from God.  His mother Mary would have been there and his constant companion Mary Magdalene and other male & female followers.