Update Tunix version

[niting]

This is required to support fused moe in MaxText. See Tunix PR: google/tunix#1385.

Description

Fused moe in Maxtext requires a feature in Tunix that is only available after the pinned commit.

Tests

Ran GRPO training and it was able to start successfully with various fused moe params set.

Checklist

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• I have performed a self-review of my code. For an optional AI review, add the gemini-review label.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have run end-to-end tests tests and provided workload links above if applicable.
• I have made or will make corresponding changes to the doc if needed, including adding new documentation pages to the relevant Table of Contents (toctree directive) as explained in our documentation.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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