test(settings): add test cases for empty setting value return value

Added a store to cache the settings configuration. The getSetting
function from useSettings is now synchronous and uses this cache.
The settings cache is set when loading the settings initially
(asnychronously).

src/App.vue

@@ -26,7 +26,7 @@ import { useRoute } from 'vue-router';
 const route = useRoute();
 
 const { getColorScheme, updateColorScheme } = useColorScheme();
-const colorScheme = ref(null);
+const colorScheme = ref(getColorScheme());
 provide('colorScheme', colorScheme);
 watch(colorScheme, (newValue) => {
     updateColorScheme(newValue);
@@ -46,7 +46,6 @@ watch(colorScheme, (newValue) => {
         document.body.classList.remove('color-scheme-auto');
     }
 });
-colorScheme.value = getColorScheme();
 
 watchEffect(() => updatePageTitle(route));
 </script>

src/features/settings/composables/useSettings.js

@@ -40,15 +40,5 @@ export const useSettings = function useSettings () {
         );
     };
 
-    /**
-     * Sets the value of a specific setting.
-     * @param {string[]} key - The setting key.
-     * @param value - The new value for the setting.
-     */
-    const setSetting = function setSetting (key, value) {
-        const settingsStore = useSettingsStore();
-        settingsStore.set(key.join('.'), value);
-    };
-
-    return { getSetting, setSetting };
+    return { getSetting };
 };