Build on macos-15-intel is flaky

[Cali0707]

As per title, our Build on macos-15-intel job is flaky. We should look into what is causing the failure(s) and make our tests handle those more gracefully

[2uasimojo]

Example flake: https://github.com/containers/kubernetes-mcp-server/actions/runs/35143963959/job/104955794045?pr=1423
Looks like the fake server is still starting when we try to hit it.
Consider a short poll loop.