Remove an unused function

packages/app-shell/src/i18n.js

@@ -8,13 +8,3 @@ const i18n = createInstance({en: en, de: de}, 'de', 'en');
 export function createI18nInstance () {
     return i18n.cloneInstance();
 }
-
-/**
- * Dummy function to mark strings as i18next keys for i18next-scanner
- *
- * @param {string} key
- * @returns {string} The key param as is
- */
-export function i18nKey(key) {
-    return key;
-}
\ No newline at end of file