Axolotls and fish that are picked up in a bucket then re-placed still count to the mob cap despite being persistent, this is not consistent with vanilla behavior. This breaks for example, https://www.youtube.com/watch?v=5bzWtA6Fy4o which relies on the bucketing mechanic to remove axolotls from the mob cap.

Server config: spigot default

Tested with fresh server, no plugins

Reason for this bug:

 In set from bucket in these mobs, ie for axoltol:

@Override public void setFromBucket(boolean flag) { 
    this.entityData.set(Axolotl.FROM_BUCKET, flag);
    this.persistenceRequired = this.isPersistent(); // ...
}

 which doesn't set the persistence to true which it should be.

Steps to reproduce:

1. Make a void world, make a hollow tinted glass cube and fill it with water. Make the floor out of stone so glow squid and axolotls can spawn.
2. Spawn at least 5 axolotls from buckets, using /data you can verify these have the bucket spawn tag but are not marked as persistent. Kill all the mobs in the water cube and note no more will spawn because the underground aquatic mob cap is full even though it shouldn't be.