chore(deps)(deps): bump i18next from 26.2.0 to 26.3.1 in /backend/admin

Bumps [i18next](https://github.com/i18next/i18next) from 26.2.0 to 26.3.1.
- [Release notes](https://github.com/i18next/i18next/releases)
- [Changelog](https://github.com/i18next/i18next/blob/master/CHANGELOG.md)
- [Commits](i18next/i18next@v26.2.0...v26.3.1)

---
updated-dependencies:
- dependency-name: i18next
  dependency-version: 26.3.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

backend/admin/package-lock.json

@@ -34,7 +34,7 @@
     "clsx": "^2.1.1",
     "cmdk": "^1.1.1",
     "date-fns": "^4.1.0",
-    "i18next": "^26.0.4",
+    "i18next": "^26.3.1",
     "lucide-react": "^1.17.0",
     "next": "^16.2.4",
     "react": "^19.2.4",