Replaces the Blueshield's Sindano with the WT-550 (and makes it only admin spawned) (#608)

## About The Pull Request

This replaces the blueshield's Sindano with the WT-550. 
I also unticked
``modular_skyrat\modules\sec_haul\code\guns\cargo_stuff.dm`` which gives
3 Sindano's for 4000 credits from cargo.

I also made it a gun case. 

![image](https://github.com/Bubberstation/Bubberstation/assets/95130227/0acc0c36-47ba-4d8f-b934-fd412639f48c)

## Why It's Good For The Game

I don't need to explain why giving the crew a round start nukie tier
weapon is bad for the game. If I edited the values, then I would have to
maintain these guns. I honestly don't care enough for Skyrat guns and
would rather revert them all back to TG.

## Changelog

🆑 StrangeWeirdKitten
del: Fully removes the ability to order the Sindano
balance: Replaces the Blueshield's Sindano with the WT-550
/🆑

modular_skyrat/modules/blueshield/code/closet.dm

@@ -29,5 +29,5 @@
 	new /obj/item/restraints/handcuffs(src)
 	new /obj/item/clothing/glasses/hud/security/sunglasses(src)
 	new /obj/item/storage/medkit/tactical/blueshield(src)
-	new /obj/item/storage/toolbox/guncase/skyrat/carwo_large_case/sindano(src)
+	new /obj/item/storage/toolbox/guncase/skyrat/carwo_large_case/wt550(src) // Bubberstation Edit
 	new /obj/item/storage/bag/garment/blueshield(src)