[NIXL] Bump NIXL version to 1.4.1

[ovidiusm]

Purpose

Bump NIXL version to 1.4.1

Currently points to a pre-release package to check if vLLM CI passes. Do not merge this; it will be removed once 1.4.1 is published.

Test Plan

[ ] vLLM CI
[ ] Internal testing in progress

Test Result

Pending

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Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.

[claude]

Claude Code Review

This pull request is from a fork — automated review is disabled. A repository maintainer can comment @claude review to run a one-time review.

[DarkLight1337]

/ci run

[github-actions]

✅ Triggered Buildkite CI #86147 for commit 57a92b6dd54f.

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @ovidiusm.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork