Refactor: Separate GPU AOT tests from the main AOT DAG

[AidenYu1673]

Description

This PR refactors the maxtext_configs_aot DAG by splitting it into two more focused DAGs:

1. maxtext_configs_aot: Now exclusively handles all TPU configuration tests.
2. maxtext_configs_aot_gpu: A new DAG dedicated to running GPU AOT tests.

Why is this change being made?

• Isolation: Separates TPU and GPU test runs, allowing them to be triggered, monitored, and re-run independently.

Validation Summary

This refactor was tested in the ml-automation-solutions-dev environment. The TPU tests have been validated, while the GPU tests will be addressed later according to team priorities.

Test Results

• TPU DAG (maxtext_configs_aot): Success ✅

  • All test cases in the refactored TPU DAG passed successfully.

• GPU DAG ( maxtext_configs_aot_gpu): Failed (Deprioritized) ⚠️

  • The new, dedicated GPU DAG failed during its run.
  • Next Steps: Since the team's current focus is on TPU stability, this failure is acknowledged.

Checklist

Before submitting this PR, please make sure (put X in square brackets):

• I have performed a self-review of my code.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have run one-shot tests and provided workload links above if applicable.
• I have made or will make corresponding changes to the doc if needed.