Spawners unsuccessfully try to summon hostile entities on peaceful difficulty

Spawner blocks and minecarts will unsuccessfully attempt to summon hostile entities when the world difficulty is set to peaceful

Steps to Reproduce:

1. Place down/summon one of the following:

   /summon spawner_minecart ~ ~ ~ {SpawnData:{entity:{id:"minecraft:slime"}},SpawnPotentials:[{weight:1,data:{entity:{id:"minecraft:slime"}}}]}

   /give @p spawner{BlockEntityTag:{SpawnData:{entity:{id:"minecraft:slime"}},SpawnPotentials:[{weight:1,data:{entity:{id:"minecraft:slime"}}}]}} 1

Expected & Observed Results:

- The spawner will display cloud particles and a slime will appear for a brief moment, then despawn.
- The spawner would not try and summon entities, as it cannot.

Screenshots/Videos:

SpawnerSummonPeaceful.mp4

Notes:

This does not affect trial spawners, which are only active in gamemodes above peaceful.