Trader llama despawn natually after being free

This bug affects 1.21.50+ .Previous versions are not tested.

If a wandering trader spawns natually or using a spawn egg, 2 trader llama will also spawn with a leash. However, if you break the leash (like, kill the trader), the llama will despawn like other mobs, instead of being presistent.

Steps to Reproduce

1.Summon a wandering trader (with 2 llama) by any method.

2.Kill the trader to free these llama.

3.Fly away a 44 blocks distance (related to your simulation distance).

4.Fly back.

Observed Result

All the llama despawn natually.

Expected Result

The llama should Not despawn, just like the previous version. They shall automatically being presistent after unleashed, even if a player haven't ride it or nametagged it.