Lets you de-select a ship outfit preview (#2779)

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## About The Pull Request

![image](https://github.com/shiptest-ss13/Shiptest/assets/47290811/e93c2ee0-9c32-4639-b630-d7c0f162cb0c)
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## Why It's Good For The Game
Currently, once you select an outfit through this menu you can't go back
to not having an outfit on your character. This fixes that (so you can
compare just your loadout gear to your loadout gear + job gear, things
like that).
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worth adding. -->

## Changelog

:cl:
tweak: You can now go back to having no ship outfit after selecting one
/🆑
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code/modules/client/preferences.dm

@@ -1240,7 +1240,11 @@ GLOBAL_LIST_EMPTY(preferences_datums)
 	if(!SSmapping)
 		return
 
-	var/datum/map_template/shuttle/ship = SSmapping.ship_purchase_list[tgui_input_list(user, "Please select which ship to preview outfits for.", "Outfit selection", SSmapping.ship_purchase_list)]
+	var/ship_selection = tgui_input_list(user, "Please select which ship to preview outfits for.", "Outfit selection", (list("None") + SSmapping.ship_purchase_list))
+	if(ship_selection == "None")
+		selected_outfit = new /datum/outfit //The base type outfit is nude
+
+	var/datum/map_template/shuttle/ship = SSmapping.ship_purchase_list[ship_selection]
 	if(!ship)
 		return