[Repo Assist] test: use TcpListener(0) for reliable free-port selection in HTTP test server#1724

dsyme merged 2 commits intomainfsprojects/FSharp.Data:mainfrom

repo-assist/eng-fix-windows-ci-port-binding-2026-04-03-003461bcee6010defsprojects/FSharp.Data:repo-assist/eng-fix-windows-ci-port-binding-2026-04-03-003461bcee6010deCopy head branch name to clipboard