The word joy was accidentally set as foes in the 1830 edition. The 1908 RLDS edition restored the original joy to the RLDS text (in accord with the reading in 𝓟); the 1981 LDS edition probably also relied on 𝓟 in restoring the original word to the LDS text (𝓞 is extant for joy but is difficult to read).
Interestingly, the word foe does not occur in the Book of Mormon text at all, but joy does.
In fact, there are some other specific references to Helaman’s joy over his army’s preservation:
Summary: Maintain in Alma 57:25 the correct joy (“the joy of our whole army”), not the foes that accidentally entered the text in the 1830 edition.