[flaky test] gapic-libraries-bom fails at install Maven modules to local repository

I believe I ran into this a couple of times recently (in last month or so).

Here is log for latest seen https://github.com/googleapis/google-cloud-java/actions/runs/30240828561/job/89897657179?pr=13896

Start with the linked GitHub Actions run and inspect the gapic-libraries-bom job where Maven modules are installed to the local repository. Reproduce the flaky failure and compare successful and failing runs; done means the install step completes reliably without the reported failure.

索引モデルが issue の本文から書いたものです。