Snowy Plains trees are not distributed with behavior packs

Analysis:

Snowy Plains trees are not distributed when using behavior pack.

Steps to Reproduce (without behavior pack, Case A):

1. Create a new world

2. Go to a snowy plains biome (example seed: 933362424 )

Steps to Reproduce (with behavior pack, Case B):

1. Create a new world

2. Go to a snowy plains biome (example seed: 933362424 )

3. Use the behavior package that you added to the issue

Observed Results :

without behavior pack, case A: It is generated with the tree distribution of actually in Snowy Plains.

In Case B: It is not generated with the distribution tree of the behavior pack in Snowy Plains.

Expected Results:

In Case B: Spruce trees are generated in Snowy Plains as expected, when the behavior packs is applied.