The command /gamerule doMobSpawning False does affect the trial spawner, making it disactivated unlike with the normal mob spawner.

What I expected to happen was...:
It should not affect it, like does happens with the mob spawner.

What actually happened was...:
This command disables the Trial Spawner.

Steps to Reproduce:
1. Use the command /gamerule doMobSpawning False
2. Go into a trial spawner. If you do the /gamerule doMobSpawning True, it will be working again.
3. It will not work, unlike with a mob spawner.