Adds more sounds to moisture traps (#94660)

## About The Pull Request

Primarily adds a loop to moisture traps which is mostly silence,
interrupted by the solemn sound of a water droplet falling. Just like
the sprite be doing, y'know?
I decided to make it a simple loop, instead of doing a little extra and
setting that sprite animation up to play only when the sound effect
plays, as I'd have to make moisture traps process to call `flick` - and
I wasn't sure if that's worth it.
The sound effect is from:
https://freesound.org/people/mattfinarelli/sounds/533146/

## Why It's Good For The Game

Adds just a drop of ambience to the maintenance shafts.

## Changelog
🆑
sound: Added more atmospheric sounds to moisture traps
/🆑

code/game/objects/structures/maintenance.dm

@@ -11,6 +11,8 @@ at the cost of risking a vicious bite.**/
 	var/obj/item/hidden_item
 	///This var determines if there is a chance to receive a bite when sticking your hand into the water.
 	var/critter_infested = TRUE
+	///A subtle loop which plays a drop of water sound every once in a while
+	var/datum/looping_sound/drip/drip_sfx
 	///weighted loot table for what loot you can find inside the moisture trap.
 	///the actual loot isn't that great and should probably be improved and expanded later.
 	var/static/list/loot_table = list(
@@ -45,11 +47,14 @@ at the cost of risking a vicious bite.**/
 		fish_source.fish_table[picked_item] = 5
 		fish_source.fish_counts[picked_item] = 1;
 	AddComponent(/datum/component/fishing_spot, fish_source)
+	drip_sfx = new(src)
+	drip_sfx.start()
 
 
 /obj/structure/moisture_trap/Destroy()
 	if(hidden_item)
 		QDEL_NULL(hidden_item)
+	drip_sfx?.stop(TRUE)
 	return ..()
 
 
@@ -71,6 +76,7 @@ at the cost of risking a vicious bite.**/
 		to_chat(user, span_warning("You need to lie down to reach into [src]."))
 		return
 	to_chat(user, span_notice("You reach down into the cold water of the basin."))
+	playsound(src,'sound/effects/submerge.ogg', 25, TRUE)
 	if(!do_after(user, 2 SECONDS, target = src))
 		return
 	if(hidden_item)
@@ -109,6 +115,7 @@ at the cost of risking a vicious bite.**/
 		return
 	hidden_item = I
 	to_chat(user, span_notice("You hide [I] inside the basin."))
+	playsound(src,'sound/effects/splash.ogg', 55, TRUE)
 
 #define ALTAR_INACTIVE 0
 #define ALTAR_STAGEONE 1