Thumbnails in catalyst have the wrong background

## 🎉 Description

Thumbnails in catalyst have the wrong background

* [x] 🐛 This is a bug report.
* [ ] 📈 This is a feature request.

## 📝 Details

There's an emote in OpenSea that has a purple background (legendary) but the rarity of the item is rare (green):

Item in DCL marketplace: https://market.decentraland.org/contracts/0x875146d1d26e91c80f25f5966a84b098d3db1fc8/items/1

Item in OpenSea: https://opensea.io/assets/matic/0x875146d1d26e91c80f25f5966a84b098d3db1fc8/105312291668557186697918027683670432318895095400549111254310977922

## 👍 Other Information

I believe this happened to items where the creator changed the rarity after creating the item, and the thumbnail generated with the previous rarity was not replaced by an updated one.