### 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)

)
ARG_PICKLE = Arg(("-p", "--pickle"), help="Serialized pickle object of the entire dag (used internally)")
ARG_JOB_ID = Arg(("-j", "--job-id"), help=argparse.SUPPRESS)
ARG_CFG_PATH = Arg(("--cfg-path",), help="Path to config file to use instead of airflow.cfg")
ARG_MAP_INDEX = Arg(("--map-index",), type=int, default=-1, help="Mapped task index")
ARG_READ_FROM_DB = Arg(("--read-from-db",), help="Read dag from DB instead of dag file", action="store_true")
ARG_MIGRATION_TIMEOUT = Arg(
    ("-t", "--migration-wait-timeout"),
    help="timeout to wait for db to migrate ",
    type=int,
    default=60,
)
ARG_DB_RESERIALIZE_DAGS = Arg(
    ("--no-reserialize-dags",),
    
    help=argparse.SUPPRESS,
    action="store_false",
    default=True,
    dest="reserialize_dags",
)
ARG_DB_VERSION__UPGRADE = Arg(
    ("-n", "--to-version"),
    help=(
        "(Optional) The airflow version to upgrade to. Note: must provide either "
        "`--to-revision` or `--to-version`."
    ),
)
ARG_DB_REVISION__UPGRADE = Arg(
    ("-r", "--to-revision"),
    help="(Optional) If provided, only run migrations up to and including this Alembic revision.",