[Blocking xmas] Snow not regenerating when snowing.

build: 572885
Summary:
Even when snowing, snow does not collect on the ground.

Impact:
Extreme Snowman relies on a mechanic involving the digging and removal of snow. The mechanic in place to redistribute the snow was to turn on weather as performance for clone and is already bad.

While they can always just recreate the world this is not great and would prefer the snow falling mechanic works otherwise will have to revert to costly clone/fill commands.

Repro steps:
1. go to a snow biome
2. dig snow out to the ground
3. do a weather toggle to make it snow

Observed behavior:
Nothing changes

Expected behavior:
snow layers should form on the ground where there was none.

Video: https://www.youtube.com/watch?v=tGvkzBG-rUs