Automate MCP conformance tests

[Azquelt]

Run the relevant tests from https://github.com/modelcontextprotocol/conformance in the build.

These require node, we can probably run that in the build using testcontainers.

Investigate how do keep the version of the conformance test up to date. We don't want to automatically use the newest version, but we need to be aware when there is a new version available.

Depends on #33698