🐛(frontend) fix fallback translations with Trans

The fallback of the Trans component didn't work
anymore after upgrade to 16.2.3 of react-i18next.
Upgrading to 16.3.3 fixed the issue.
We added a test to cover this case.

src/frontend/apps/impress/package.json

@@ -62,7 +62,7 @@
     "react": "*",
     "react-aria-components": "1.13.0",
     "react-dom": "*",
-    "react-i18next": "16.2.3",
+    "react-i18next": "16.3.3",
     "react-intersection-observer": "10.0.0",
     "react-resizable-panels": "3.0.6",
     "react-select": "5.10.2",