initialize language switch test suite with beforeEach setup

src/utils/__tests__/LanguageSwitchButton.test.js

@@ -37,4 +37,12 @@ vi.mock('@/features/icons/components/Icon.vue', () => ({
         name: 'Icon',
         template: '<span>Icon</span>'
     }
-}));
+}));
+
+describe('LanguageSwitchButton.vue', () => {
+    beforeEach(() => {
+        vi.clearAllMocks();
+        localStorage.clear();
+        document.documentElement.lang = '';
+        document.documentElement.dir = '';
+    });