Powder Snow emits particles when spectators move through it

Summary:
Powder Snow emits particles when spectators move through it

Steps to reproduce:

1. Place Powder Snow.

2. Switch to spectator mode (/gamemode spectator).

3. Move inside Powder Snow.

Observed results:
The player can spawn particles in spectator mode.

Expected results:
Particles should not spawn from the player in spectator mode.