Some trial spawners in trial chambers spawn mobs without persistence

Certain types of trial spawners that generate in the trial chambers will fail to set the spawned mobs as persistent, allowing the player to despawn the mobs and claim their reward without fighting.

Steps to Reproduce

1. Locate a trial spawner that is affected by the bug.
   Example:

   Seed: -3955354196018892310
   /execute in minecraft:overworld run tp @s 40.00 -35.00 191.77 -643.71 17.55

2. Activate the trial spawner by switching to survival.
3. Move more than 128 blocks from the spawner and wait there for ~10s.
4. Return to the spawner.

Expected Result

The mobs remain inside the room.

Actual Result

All of the mobs spawned by the trial spawner despawn causing the trial spawner to eject loot.