chore(deps): bump react-dom from 19.2.5 to 19.2.6 in /testsite

Bumps [react-dom](https://github.com/facebook/react/tree/HEAD/packages/react-dom) from 19.2.5 to 19.2.6.
- [Release notes](https://github.com/facebook/react/releases)
- [Changelog](https://github.com/facebook/react/blob/main/CHANGELOG.md)
- [Commits](https://github.com/facebook/react/commits/v19.2.6/packages/react-dom)

---
updated-dependencies:
- dependency-name: react-dom
  dependency-version: 19.2.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

testsite/package-lock.json

@@ -24,7 +24,7 @@
     "json-schema-faker": "^0.6.1",
     "jsonpos": "^4.1.2",
     "react": "^19.2.5",
-    "react-dom": "^19.2.5",
+    "react-dom": "^19.2.6",
     "react-markdown": "^10.0.0",
     "react-toastify": "^11.0.3"
   },