Summary:
The experience bar in the trading GUI is not retextured in the Adventure Time and Steven Universe resource packs.

Steps to Reproduce:

1. Open a world with the Adventure Time or Steven Universe resource pack enabled
2. Spawn a villager
3. Open the trading GUI
4. Look at the experience bar

Observed Results:
The experience bar uses the default texture.

Expected Results:
The experience bar should be retextured, similarly to the player's experience bar.

Screenshot: