Simplify maybe_initialize_jax_distributed_system()

[SurbhiJainUSC]

Description

This PR refactors the JAX distributed initialization process by simplifying the maybe_initialize_jax_distributed_system() function.

• Why is this change being made: To improve code readability.
• The problem being solved: The previous implementation of the distributed setup had unnecessary complexity and boilerplate.
• Why this is a good solution: It consolidates the logic for checking and initializing the JAX distributed system, making the initialization flow easier to maintain.

Tests

CI tests

Checklist

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• 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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