### Description

Currently, the `airflow variables export` command requires an explicit file path and does not support output to stdout. However connections can be printed to stdout using `airflow connections export -`. This inconsistency between the two export commands can lead to confusion and limits the flexibility of the variables export command.

### Use case/motivation

To bring some consistency, similar to connections, variables should also be printed to STDOUT, using `-` instead of filename. 

### Related issues

_No response_

### Are you willing to submit a PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

KUBERNETES_COMMANDS = (
    ActionCommand(
        name="cleanup-pods",
        help=(
            "Clean up Kubernetes pods "
            "(created by KubernetesExecutor/KubernetesPodOperator) "
            "in evicted/failed/succeeded/pending states"
        ),
        func=lazy_load_command("airflow.cli.commands.kubernetes_command.cleanup_pods"),
        args=(ARG_NAMESPACE, ARG_MIN_PENDING_MINUTES, ARG_VERBOSE),
    ),
    ActionCommand(
        name="generate-dag-yaml",
        help="Generate YAML files for all tasks in DAG. Useful for debugging tasks without "
        "launching into a cluster",
        func=lazy_load_command("airflow.cli.commands.kubernetes_command.generate_pod_yaml"),
        args=(ARG_DAG_ID, ARG_EXECUTION_DATE, ARG_SUBDIR, ARG_OUTPUT_PATH, ARG_VERBOSE),
    ),
)
JOBS_COMMANDS = (
    ActionCommand(
        name="check",
        help="Checks if job(s) are still alive",
        func=lazy_load_command("airflow.cli.commands.jobs_command.check"),
        args=(
            ARG_JOB_TYPE_FILTER,
            ARG_JOB_HOSTNAME_FILTER,
            ARG_JOB_HOSTNAME_CALLABLE_FILTER,
            ARG_JOB_LIMIT,
            ARG_ALLOW_MULTIPLE,