I do think it's odd that there isn't a parallel "problem" for the substantive "independent" (one who is not a dependant). I checked the OED and an -ant form doesn't seem to be mentioned at all (not even as obs.).
Well, I'm from the USA but have lived here in the UK for 11 years. Sorry, but the word dependAnt is just plain wrong in the article -- wrong on both sides of the Atlantic. I think it was just an error in proofreading. We would use dependAnt when referring to a person who is dependEnt on someone or something.