But is it actually wrong? There is no confirmed date for the first contact between Cardassians and the Federation. Just speculation that it was in the early 24th Century. Also it's possible that while these two haven't met they could still be aware of each other and through some trading with other races they came upon Kanar.
Nope. If I'd thought it was "wrong" for that reason, I'd have said that instead. Rather, it's POINTLESS, except (as I said) as a bit of somewhat divisive "fanwankery."
I don't have any personal issue with it being Kanar (though I'd have a problem were it Tranya). I just think it's silly to use Kanar. Just have her get "a drink."
The only drinks that I'd say would deserve mention in this film (and even then, only as bits of throw-away trivia!) would be Scotch Whiskey (and that would be for one particular character), Saurian Brandy (for another particular character), and perhaps Mint Julips (for yet another particular character).
Otherwise, just stick to "a drink" and leave it at that.