[ci] Non-verbose llvm download in Buildkite (#23731)
[ci] Non-verbose llvm download in Buildkite (#23731)

What: Use wget -nv in Buildkite environments
Why: The llvm download currently clutters the log output as it's not rendered correctly, thus we should silence it.

Result: Logs are finally readable again in Buildkite without download: https://buildkite.com/ray-project/ray-builders-pr/builds/28916#25e8965a-d18b-49a1-8e29-200365b13c53
ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray