Add a unit test to check that maploaded simple/basic mobs are in an environment they can survive in. (#82180)

## About The Pull Request
I've recently noticed that the maploaded penguins from the snowdin away
mission were dying from unsafe atmos/temperature. This sparked the idea
of making a (focus only) unit test that would prevent this sort of
issues from happening.

This PR also implements the usage of the `atmos_requirements` and
`body_temp_sensitive` elements for simple animals too, cutting down the
copypaste.

## Why It's Good For The Game
More unit tests to make sure things are done correctly.

## Changelog

🆑
fix: Made sure that mapped critters (i.e. penguins on the snow cabin
away mission) can survive in the environment they're spawned in.
/🆑

code/game/objects/effects/spawners/random/trash.dm

@@ -134,6 +134,13 @@
 		/obj/effect/spawner/random/trash/cigbutt = 2,
 	)
 
+/obj/effect/spawner/random/trash/grime/Initialize(mapload)
+	if(mapload)
+		var/turf/location = get_turf(loc)
+		if(location.initial_gas_mix != OPENTURF_DEFAULT_ATMOS && location.initial_gas_mix != OPENTURF_DIRTY_ATMOS)
+			loot -= /mob/living/basic/cockroach
+	return ..()
+
 /obj/effect/spawner/random/trash/moisture
 	name = "water hazard spawner"
 	icon_state = "caution"
@@ -150,6 +157,13 @@
 		/mob/living/basic/axolotl = 1,
 	)
 
+/obj/effect/spawner/random/trash/moisture/Initialize(mapload)
+	if(mapload)
+		var/turf/location = get_turf(loc)
+		if(location.initial_gas_mix != OPENTURF_DEFAULT_ATMOS && location.initial_gas_mix != OPENTURF_DIRTY_ATMOS)
+			loot -= list(/mob/living/basic/frog, /mob/living/basic/axolotl)
+	return ..()
+
 /obj/effect/spawner/random/trash/graffiti
 	name = "random graffiti spawner"
 	icon_state = "rune"