Fixed mob spawn restricted species validations

modular_doppler/modular_mob_spawn/code/mob_spawn.dm

@@ -3,7 +3,7 @@
 	var/list/restricted_species = list()
 
 /obj/effect/mob_spawn/ghost_role/create(mob/mob_possessor, newname)
-	if(restricted_species && !(mob_possessor?.client?.prefs?.read_preference(/datum/preference/choiced/species) in restricted_species))
+	if(restricted_species.len  && !(mob_possessor?.client?.prefs?.read_preference(/datum/preference/choiced/species) in restricted_species))
 		var/text = "Current loaded character doesn't match required species: "
 		var/i = 1
 		for(var/datum/species/speciesItem as anything in restricted_species)