### 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)

"""Displays variable by a given name."""
    try:
        if args.default is None:
            var = Variable.get(args.key, deserialize_json=args.json)
            print(var)
        else:
            var = Variable.get(args.key, deserialize_json=args.json, default_var=args.default)
            print(var)
    except (ValueError, KeyError) as e:
        raise SystemExit(str(e).strip("'\""))
@cli_utils.action_cli
@providers_configuration_loaded
def variables_set(args):