Bump mcp from 1.11.0 to 1.23.0 in /src/backend

Bumps [mcp](https://github.com/modelcontextprotocol/python-sdk) from 1.11.0 to 1.23.0.
- [Release notes](https://github.com/modelcontextprotocol/python-sdk/releases)
- [Changelog](https://github.com/modelcontextprotocol/python-sdk/blob/main/RELEASE.md)
- [Commits](modelcontextprotocol/python-sdk@v1.11.0...v1.23.0)

---
updated-dependencies:
- dependency-name: mcp
  dependency-version: 1.23.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

src/backend/requirements.txt

@@ -118,7 +118,7 @@ jsonschema-specifications==2025.4.1
     # via jsonschema
 marshmallow==4.0.0
     # via environs
-mcp==1.11.0
+mcp==1.23.0
     # via openai-agents
 msal==1.32.3
     # via