M3-L Pattern Light Armor Added to IO Prep (#5574)

# About the pull request

Adds M3-L Pattern Light Armor to the clothing vendor in Intelligence
Officer (IO) prep.

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# Explain why it's good for the game

1. M3-L Pattern Light armor is a very commonly used asset by IOs. 
2. It is currently acquirable via the Marine Squad Preps in nearly
endless supply.
3. This change eliminates the need for IOs to go to the Marine Prep for
light armor, improving quality of life and reducing prep time.
# Testing Photographs and Procedure

![image](https://github.com/cmss13-devs/cmss13/assets/32654903/3e3c9507-03cd-48d9-bf06-b3ec8331bd27)

# Changelog
:cl: NervanCatos
qol: added M3-L Pattern Light Armor to IO Prep
/:cl:

Note: I accidentally deleted the repo for the original PR #5567, this is
a clone.

code/game/machinery/vending/vendor_types/intelligence_officer.dm

@@ -68,6 +68,7 @@ GLOBAL_LIST_INIT(cm_vending_clothing_intelligence_officer, list(
 
 		list("ARMOR (CHOOSE 1)", 0, null, null, null),
 		list("XM4 Pattern Intel Armor", 0, /obj/item/clothing/suit/storage/marine/medium/rto/intel, MARINE_CAN_BUY_ARMOR, VENDOR_ITEM_MANDATORY),
+		list("M3-L Pattern Light Armor", 0, /obj/item/clothing/suit/storage/marine/light, MARINE_CAN_BUY_ARMOR, VENDOR_ITEM_MANDATORY),
 		list("Service Jacket", 0, /obj/item/clothing/suit/storage/jacket/marine/service, MARINE_CAN_BUY_ARMOR, VENDOR_ITEM_MANDATORY),
 
 		list("BACKPACK (CHOOSE 1)", 0, null, null, null),