Add e2e test suite for Airflow event-driven DAGs with Apache Kafka

[jason810496]

Why

Airflow 3 introduces event-driven DAGs with Assets, AssetWatchers, and MessageQueueTrigger to enable reactive, message-driven pipelines. This PR adds a comprehensive e2e
test suite to verify that Kafka-based event routing works correctly, including proper handling of malformed messages and dead-letter queues.

What

• Dag pattern: Implemented a producer-consumer pattern where producer sends 9 messages (8 valid orders + 1 malformed) to a Kafka topic, and consumer triggers 9 times via AssetWatcher
• Test verification: Consumer Dag uses retries (3), short-circuit on malformed messages, and routes failures to a dead-letter queue topic
• CI integration: Extended selective-checks to detect event-driven test file changes and trigger the suite; added workflow inputs/outputs for test mode selection
• Kafka integration: The kafka.yaml and update_run.sh are copied from breeze --integration kafka

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