World change causes crash with Mo'Creatures installed

[twothe]

In at.feldim2425.moreoverlays.lightoverlay.integration.CustomSpawnerLightScanner

    List<Biome.SpawnListEntry> possibleSpawns = CustomSpawner.instance().getPossibleCustomCreatures(world, environment.entitySpawnTypes.get("MONSTER"), pos.getX(), pos.getY(), pos.getZ());

    return !possibleSpawns.isEmpty();

The returned list possibleSpawns can be null when changing worlds (i.E. to the Nether or back), which will then instantly result in a crash. This can also happen when logging in, which then causes the world to be unplayable until MoreOverlays is deactivated.

Using Minecraft 1.12 with Forge 2854. MoreOverlays 21.7.19, CustomMobSpawner 3.11.5.

[Pyker]

This is a duplicate of #72