Fix triggerer CrashLoopBackOff when json_logs is enabled

[safaehar]

What

TriggerRunnerSupervisor._process_log_messages_from_subprocess primes itself by calling airflow.sdk.log.configure_logging() with no arguments. json_output defaults to False, so this call reconfigures structlog globally and installs the text WriteLogger factory — overwriting the bytes BytesLogger factory that startup set up when [logging] json_logs = True.

The stdout/stderr forwarders (_create_log_forwarder → forward_to_log) are already wrapped with the JSON (bytes) processor chain but bind their underlying logger lazily. As soon as a trigger subprocess writes to stdout/stderr — e.g. an import-time DeprecationWarning from a provider trigger that imports a heavy client such as KubernetesPodTrigger (kubernetes) or S3KeyTrigger (boto3) — the lazy bind resolves against the now-text factory, and WriteLogger.msg does message + "\n" on bytes produced by the JSON renderer:

TypeError: can't concat str to bytes
  File ".../structlog/_output.py", line 217, in msg
    self._write(message + "\n")

This crashes the TriggerRunnerSupervisor.run loop and the triggerer enters CrashLoopBackOff. It only manifests when json_logs is enabled and the triggerer actually runs a trigger whose subprocess emits to stdout/stderr — idle triggerers and those running only quiet triggers (DateTimeTrigger, etc.) never reach forward_to_log, which is why the crash looks intermittent across deployments.

Fix

Pass json_output from the [logging] json_logs config (the same conf.getboolean("logging", "json_logs", fallback=False) used elsewhere, e.g. airflow/logging_config.py) so the global structlog factory stays consistent with the rest of the process. This matches the already-hardcoded logging_processors(json_output=True) a few lines below.

Tests

Adds a parametrized regression test asserting _process_log_messages_from_subprocess calls configure_logging(json_output=<json_logs>) for both True and False.

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