Make Radios appear on character sprites again (#21932)

Back-end change caused radios to vanish due to not having explicit
contained_sprite setting.

You can see clip-on radios, headsets, etc. on your characters again.

code/game/objects/items/devices/radio/headset.dm

@@ -4,6 +4,7 @@
 	icon = 'icons/obj/item/radio/headset.dmi'
 	icon_state = "headset"
 	item_state = "headset"
+	contained_sprite = TRUE
 	matter = list(MATERIAL_ALUMINIUM = 75)
 	subspace_transmission = TRUE
 	canhear_range = 0 // can't hear headsets from very far away