Hi there, that Q comes up on this forum every now + then. Those are the larva of the Dermestid beetle, they are used as cleaners to eat up shed + poo from the crickets and are harmles to your beardie. Beardies actually like them but since they [ the worms ] are scavengers it's not advised to feed them to your beardie on purpose in large numbers, but they are not toxic one bit. Many b.d. owners have dragons that ate this , including mine. No worry at all.
Oh, they do turn in to a small black beetle and can fly a bit at that stage so just watch that you don't get a number of them in your house. Not that it's a problem, I've had about 25 years worth of crix in my hose [ along with those larva ] and not one thing has ever done damage or escaped + became an infestation.