Fixes vendor showing weird glass icons (#71929)

## About The Pull Request
Fixes vendor showing weird glass icons
## Why It's Good For The Game
bug fix good
## Changelog
🆑
fix: vendor no longer shows glass icons in a specific condition
/🆑

code/modules/asset_cache/assets/vending.dm

@@ -2,7 +2,16 @@
 	name = "vending"
 
 /datum/asset/spritesheet/vending/create_spritesheets()
-	for (var/k in GLOB.vending_products)
+	// initialising the list of items we need
+	var/target_items = list()
+	for(var/obj/machinery/vending/vendor as anything in typesof(/obj/machinery/vending))
+		vendor = new vendor() // It seems `initial(list var)` has nothing. need to make a type.
+		for(var/each in list(vendor.products, vendor.premium, vendor.contraband))
+			target_items |= each
+		qdel(vendor)
+
+	// building icons for each item
+	for (var/k in target_items)
 		var/atom/item = k
 		if (!ispath(item, /atom))
 			continue