No problem! Never seen that at my local Petco, how interesting. It's possible it hitchhiked in from somewhere else, damselfly nymphs live in water, and more than a few people have had them come in on plants. Those ones are harmless in the nymph and adult stage, dragonfly nymphs will eat your fish and the adults will bite you.
That's all pretty cool, tbh
those are just flightless fruit flies. i highly doubt the damselfly was in the tube with them, as @Rtessy said, the larvae are aquatic. it probably came in your house or its larva was on a plant or in your tank without you noticing.