Fixes ballistic weapons not making any firing sound (#86250)

## About The Pull Request

Fixes https://github.com/NovaSector/NovaSector/issues/4337

https://github.com/tgstation/tgstation/pull/85470 added some checks in
`/obj/item/gun/ballistic/shoot_live_shot()` that were causing runtimes
in probably most of the ballistic gun types. To see for yourself just
take out a revolver and shoot it a few times, then check the runtimes
log.

The runtime was preventing the parent
`/obj/item/gun/ballistic/shoot_live_shot()` from being called, which is
where the firing sound gets played.

Fix is just acknowledging that `chambered` can be null at this point in
the call chain and adding a quick check in there for good measure. Also
fixes the runtime here, though that one didn't cause any functional bugs
apart from polluting the log since it occurs at the end of the proc.


![KZXgDrEAnV](https://github.com/user-attachments/assets/f22dcc6a-fffd-4d10-abdd-e5d98856939b)
 
Also adds a missing multiline list comma that I noticed cough.

## Why It's Good For The Game

Guns go boom again.

## Changelog

🆑
fix: due to a clerical error, all ballistic guns were shipping with
built-in silencers. this has been resolved-they will now make noise once
again when fired.
/🆑

code/datums/components/face_decal.dm

@@ -118,7 +118,8 @@
 GLOBAL_LIST_INIT(creamable, typecacheof(list(
 	/mob/living/carbon/human,
 	/mob/living/basic/pet/dog/corgi,
-	/mob/living/silicon/ai)))
+	/mob/living/silicon/ai,
+)))
 
 /datum/component/face_decal/creampie/Initialize()
 	. = ..()

code/modules/projectiles/gun.dm

@@ -220,7 +220,7 @@
 				ignored_mobs = user
 		)
 
-	if(chambered.integrity_damage)
+	if(chambered?.integrity_damage)
 		take_damage(chambered.integrity_damage, sound_effect = FALSE)
 
 /obj/item/gun/atom_destruction(damage_flag)

code/modules/projectiles/guns/ballistic.dm

@@ -480,6 +480,8 @@
 	return ..()
 
 /obj/item/gun/ballistic/shoot_live_shot(mob/living/user, pointblank = 0, atom/pbtarget = null, message = 1)
+	if(isnull(chambered))
+		return ..()
 	if(can_misfire && chambered.can_misfire != FALSE)
 		misfire_probability += misfire_percentage_increment
 		misfire_probability = clamp(misfire_probability, 0, misfire_probability_cap)