The 1830 typesetter accidentally inserted the word as in this sentence. As might be expected, the subsequent 1837 edition removed this typo from the text. What we seem to have here is a kind of dittography where John Gilbert correctly set us from 𝓟 but then misread the us in 𝓟 as as and ended up inserting that word after the us.
Summary: Maintain the original text in Alma 58:11, that is, without as before great faith.