### 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)

cmd = command._asdict()
    cmd["args"] = (arg for arg in command.args if arg is not ARG_DAG_ID)
    return ActionCommand(**cmd)
dag_cli_commands: list[CLICommand] = [
    GroupCommand(
        name="dags",
        help="Manage DAGs",
        subcommands=[
            _remove_dag_id_opt(sp)
            for sp in DAGS_COMMANDS
            if sp.name in ["backfill", "list-runs", "pause", "unpause", "test"]
        ],
    ),
    GroupCommand(
        name="tasks",
        help="Manage tasks",
        subcommands=[_remove_dag_id_opt(sp) for sp in TASKS_COMMANDS if sp.name in ["list", "test", "run"]],
    ),
]
DAG_CLI_DICT: dict[str, CLICommand] = {sp.name: sp for sp in dag_cli_commands}