Fix airflow plugins and dags pause printing prose with --output json

[ColtenOuO]

Sumarry

When nothing matched, airflow plugins and airflow dags pause / airflow dags unpause printed a hard-coded prose message ("No plugins loaded", "No unpaused DAGs were found") before reaching AirflowConsole().print_as, so --output json and --output yaml were ignored on that path and callers piping into jq or a YAML parser got output they cannot parse.

The [] output comes from AirflowConsole in airflow-core/src/airflow/cli/simple_table.py: print_as dispatches on --output, and for an empty list print_as_json renders json.dumps([]) and print_as_yaml renders yaml.dump([]), both of which produce [], while print_as_table / print_as_plain_table print "No data found". The other list-style commands (e.g. airflow dags list, airflow pools list, airflow variables list) hand the possibly-empty result straight to print_as and therefore already behave this way, and airflow-core/docs/howto/usage-cli.rst documents it ("the default output when there are no errors is No data found, and the json output is []"). airflow teams list was aligned with that convention in #72945.

This PR makes the two remaining commands follow the same convention for structured output by passing the empty result to print_as for json / yaml.

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

• Yes — Claude Code (Opus 5)