chore(client): migrate i18n/configForTest.js to TS (#45624)

client/i18n/config-for-tests.ts

@@ -0,0 +1,21 @@
+import i18n from 'i18next';
+import { initReactI18next } from 'react-i18next';
+
+i18n
+  .use(initReactI18next)
+  .init({
+    debug: true,
+    defaultNS: 'translations',
+    fallbackLng: 'en',
+    interpolation: {
+      escapeValue: false
+    },
+    lng: 'en',
+    ns: ['translations'],
+    resources: { en: { translations: {} } }
+  })
+  .catch((error: Error) => {
+    throw Error(error.message);
+  });
+
+export default i18n;