Initially the spinner was only used in OutfitPreview, where the background was always pretty dark. Now that we use it in more general contexts, we need a light/dark distinction!
Also went and standardized out the `size` props
(the permissioning happens on the backend in the prev change! but yeah we send the auth token in the headers, so the backend knows who you are and whether to show you private data)
(also it is just owned items not in any list!)
