build(deps): bump @modelcontextprotocol/client in /ui

Bumps [@modelcontextprotocol/client](https://github.com/modelcontextprotocol/typescript-sdk) from 2.2.0 to 2.3.1.
- [Release notes](https://github.com/modelcontextprotocol/typescript-sdk/releases)
- [Commits](https://github.com/modelcontextprotocol/typescript-sdk/compare/@modelcontextprotocol/client@2.2.0...@modelcontextprotocol/client@2.3.1)

---
updated-dependencies:
- dependency-name: "@modelcontextprotocol/client"
  dependency-version: 2.3.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

ui/package-lock.json

@@ -16,7 +16,7 @@
   },
   "dependencies": {
     "@github/markdown-toolbar-element": "^2.2.3",
-    "@modelcontextprotocol/client": "^2.0.0",
+    "@modelcontextprotocol/client": "^2.3.1",
     "@modelcontextprotocol/ext-apps": "^2.0.3",
     "@primer/octicons-react": "^19.38.0",
     "@primer/primitives": "^11.10.0",