### 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)

" includes descriptions, examples, variables. Comment out everything.",
    action="store_true",
)
ARG_VERBOSE = Arg(("-v", "--verbose"), help="Make logging output more verbose", action="store_true")
ARG_LOCAL = Arg(("-l", "--local"), help="Run the task using the LocalExecutor", action="store_true")
ARG_DONOT_PICKLE = Arg(
    ("-x", "--donot-pickle"),
    help=(
        "Do not attempt to pickle the DAG object to send over "
        "to the workers, just tell the workers to run their version "
        "of the code"
    ),
    action="store_true",
)
ARG_BF_IGNORE_DEPENDENCIES = Arg(
    ("-i", "--ignore-dependencies"),
    help=(
        "Skip upstream tasks, run only the tasks "
        "matching the regexp. Only works in conjunction "
        "with task_regex"
    ),
    action="store_true",
)
ARG_BF_IGNORE_FIRST_DEPENDS_ON_PAST = Arg(
    ("-I", "--ignore-first-depends-on-past"),
    help=(
        "Ignores depends_on_past dependencies for the first "
        "set of tasks only (subsequent executions in the backfill "
        "DO respect depends_on_past)"
    ),