Add Github workflow to trigger MaxText E2E Airflow DAG

[SurbhiJainUSC]

Description

This change adds a GitHub workflow that interfaces with the Airflow REST API to trigger the maxtext_e2e_tests DAG. The workflow passes essential metadata to the Airflow instance.

Tests

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commands to reproduce.

Checklist

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• 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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