It seems the lizard was dead for a long time before ending up in the spiders web. Spiders don’t have the ability to ‘eat’ like other animals. They inject prey with a fluid which turns the preys insides into a smoothie which the spider drinks with its fangs, using them like straws. They don’t have the mouths other animals have, they don’t chew, grind, and rip away at dead prey items. So if this was the work of a spider, the lizard would be shrivelled up like a raisin, assuming a spider that small could eat a lizard this large in the first place. So it’s obvious the lizard died of some other cause and a person found it and tossed the remaining corpse into the spiders web. Spiders will eat(or attempt to eat) deceased animals from time to time.