Fix TriggerDagRunOperator API errors bypassing retries

[ahmadalguydi]

Summary

• route API/runtime errors raised while handling DagRunTriggerException through the normal task-failure path
• preserve the existing behavior for unrelated exceptions
• add regression coverage proving a missing target DAG can transition to UP_FOR_RETRY

Validation

• python -m compileall -q task-sdk/src/airflow/sdk/execution_time/task_runner.py task-sdk/tests/task_sdk/execution_time/test_task_runner.py
• git diff --check
• Focused pytest was attempted, but this Windows checkout cannot complete Airflow\x27s provider-dependency bootstrap: the repository script encounters an existing cp1252 decode failure in a provider file. The failure occurs before test collection.

Fixes #70683