### 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)

help="Reserialize all DAGs by parsing the DagBag files",
        description=(
            "Drop all serialized dags from the metadata DB. This will cause all DAGs to be reserialized "
            "from the DagBag folder. This can be helpful if your serialized DAGs get out of sync with the "
            "version of Airflow that you are running."
        ),
        func=lazy_load_command("airflow.cli.commands.dag_command.dag_reserialize"),
        args=(
            ARG_CLEAR_ONLY,
            ARG_SUBDIR,
            ARG_VERBOSE,
        ),
    ),
)
TASKS_COMMANDS = (
    ActionCommand(
        name="list",
        help="List the tasks within a DAG",
        func=lazy_load_command("airflow.cli.commands.task_command.task_list"),
        args=(ARG_DAG_ID, ARG_TREE, ARG_SUBDIR, ARG_VERBOSE),
    ),
    ActionCommand(
        name="clear",
        help="Clear a set of task instance, as if they never ran",
        func=lazy_load_command("airflow.cli.commands.task_command.task_clear"),
        args=(
            ARG_DAG_ID,
            ARG_TASK_REGEX,
            ARG_START_DATE,
            ARG_END_DATE,