feat: upgrade react-i18next from 11.18.6 to 12.0.0

Snyk has created this PR to upgrade react-i18next from 11.18.6 to 12.0.0.

See this package in npm:
https://www.npmjs.com/package/react-i18next

See this project in Snyk:
https://app.snyk.io/org/gluu-gca/project/9a1b2f96-22f2-4325-bf59-06e117632057?utm_source=github&utm_medium=referral&page=upgrade-pr

admin-ui/package.json

@@ -158,7 +158,7 @@
     "react-error-boundary": "^3.1.0",
     "react-grid-layout": "^1.1.1",
     "react-helmet": "^6.1.0",
-    "react-i18next": "^11.15.3",
+    "react-i18next": "^12.0.0",
     "react-idle-timer": "^5.4.2",
     "react-month-picker": "^2.2.1",
     "react-responsive": "^9.0.0-beta.10",