### 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)

"value you set for 'AIRFLOW_HOME' config you set in 'airflow.cfg' "
    ),
    default="[AIRFLOW_HOME]/dags" if BUILD_DOCS else settings.DAGS_FOLDER,
)
ARG_START_DATE = Arg(("-s", "--start-date"), help="Override start_date YYYY-MM-DD", type=parsedate)
ARG_END_DATE = Arg(("-e", "--end-date"), help="Override end_date YYYY-MM-DD", type=parsedate)
ARG_OUTPUT_PATH = Arg(
    (
        "-o",
        "--output-path",
    ),
    help="The output for generated yaml files",
    type=str,
    default="[CWD]" if BUILD_DOCS else os.getcwd(),
)
ARG_DRY_RUN = Arg(
    ("-n", "--dry-run"),
    help="Perform a dry run for each task. Only renders Template Fields for each task, nothing else",
    action="store_true",
)
ARG_PID = Arg(("--pid",), help="PID file location", nargs="?")
ARG_DAEMON = Arg(
    ("-D", "--daemon"), help="Daemonize instead of running in the foreground", action="store_true"
)
ARG_STDERR = Arg(("--stderr",), help="Redirect stderr to this file")
ARG_STDOUT = Arg(("--stdout",), help="Redirect stdout to this file")
ARG_LOG_FILE = Arg(("-l", "--log-file"), help="Location of the log file")
ARG_YES = Arg(
    ("-y", "--yes"),
    help="Do not prompt to confirm. Use with care!",