Bump chai from 5.2.1 to 6.2.1 in /js

Bumps [chai](https://github.com/chaijs/chai) from 5.2.1 to 6.2.1.
- [Release notes](https://github.com/chaijs/chai/releases)
- [Changelog](https://github.com/chaijs/chai/blob/main/History.md)
- [Commits](chaijs/chai@v5.2.1...v6.2.1)

---
updated-dependencies:
- dependency-name: chai
  dependency-version: 6.2.1
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

js/libs/keycloak-admin-client/package.json

@@ -49,7 +49,7 @@
     "@types/lodash-es": "^4.17.12",
     "@types/mocha": "^10.0.10",
     "@types/node": "^24.0.15",
-    "chai": "^5.2.1",
+    "chai": "^6.2.1",
     "lodash-es": "^4.17.21",
     "mocha": "^11.7.1",
     "ts-node": "^10.9.2"