Prevent deferrable KubernetesPodOperator log parsing from blocking the triggerer event loop

[aeroyorch]

Prevent deferrable KubernetesPodOperator log parsing from blocking the triggerer event loop when default_deferrable is True with get_logs and logging_interval set, which stales on verbose pods.
Offload that work to a thread so the loop stays responsive.

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Claude Opus 4.8 for tests.

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[aeroyorch]

I believe the CI errors are unrelated to the current changes.