only single selected theme or custom background at once

interface/src/hooks/ThemeManagment.tsx

@@ -1,5 +1,6 @@
 interface ThemeList {
   themes: string[];
+  selectedTheme: string;
 }
 
 export const downloadTheme = async (themeName: string, themeURL: string) => {
@@ -34,14 +35,13 @@ export const listThemes = async () => {
   // send message to the background script
   const response: ThemeList = await chrome.runtime.sendMessage({
     type: 'currentTab',
-    info: 'ListThemes',
-    body: {}
+    info: 'ListThemes'
   });
 
   // response.themes is an array of strings that are identical to the theme names that we loop over. Use this list to see which ones are downloaded and which ones need to see the download icon.
   console.log("Response: ", response);
 
-  return response.themes;
+  return response;
 }
 
 export const disableTheme = async () => {