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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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[gobbleturk]

there may be weird interactions with pytest, - it looks like this is heavily mocked, so jax.distributed.initialize is never really called? Could you include a comment if this is the case. If you don't mock I am not sure this will work