Fix misc pylint issues.

[NicoGrande]

Description

Fix misc pylint issues.

Tests

CI

Checklist

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[codecov]

Codecov Report

❌ Patch coverage is 37.50000% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/maxtext/layers/decoders.py	37.50%	1 Missing and 4 partials ⚠️

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