Honor verbose logging for Celery workers

[jx2lee]

Fixes airflow celery worker -v so the Celery worker receives --loglevel DEBUG instead of only updating Airflow's root logger.

closes: #46990

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Was generative AI tooling used to co-author this PR?

• Yes — Codex (GPT-5)

Generated-by: Codex (GPT-5) following the guidelines

[Vamsi-klu]

This one is straightforward. The if args.verbose: celery_log_level = "DEBUG" sits right after the CELERY_LOGGING_LEVEL/LOGGING_LEVEL resolution in worker() and before celery_log_level gets dropped into the --loglevel slot of options, so -v actually rides through to celery_app.worker_main now. args.verbose is the shared ARG_VERBOSE store_true wired into the worker command in definition.py, so it is always set and forcing DEBUG only ever raises verbosity, never lowers a configured level. The added test asserts the exact --loglevel DEBUG slot. Only stray thought is whether the generic -v help text ("Make logging output more verbose") makes this discoverable for the celery worker case, but that is non blocking.

[Miretpl]

I will wait with merge until current in-progress provider release will be finished.