Trial spawners' loot is not deterministic

Trial spawners' (both normal and ominous) loot is not based on the seed of the world.

Steps to reproduce the issue

1. Create a new world.

2. Find a trial spawner.

3. Kill all the mobs that it spawns and note down what kind of loot it gives.

4. Repeat steps 2 – 3 with different trial spawners.

5. Create a new world with the same seed as the previous world.

6. Go to the same trial spawners as before, kill the mobs and note down what they give this time.

7. Notice how the loot (hopefully) is not the same as on the first world, even though the same seed was used and the same trial spawners were checked.

Expected result

Since the same world seed was used, I expected to get the same loot from trial spawners, as that is the case for other loot containers like chests and vaults.

Actual result

The loot from trial spawners is fully random even if the same seed was used.