### Body

The CLI:

`airflow variables set [-h] [-j] [-v] key VALUE`

https://airflow.apache.org/docs/apache-airflow/stable/cli-and-env-variables-ref.html#set_repeat1

Doesn't support adding description though column exists and we support it from Rest API:
https://airflow.apache.org/docs/apache-airflow/stable/stable-rest-api-ref.html#operation/post_variables

**The Task:**

Allow to set description from cli command

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
ARG_DB_TABLES,
            ARG_DB_DRY_RUN,
            ARG_DB_CLEANUP_TIMESTAMP,
            ARG_VERBOSE,
            ARG_YES,
            ARG_DB_SKIP_ARCHIVE,
        ),
    ),
    ActionCommand(
        name="export-archived",
        help="Export archived data from the archive tables",
        func=lazy_load_command("airflow.cli.commands.db_command.export_archived"),
        args=(
            ARG_DB_EXPORT_FORMAT,
            ARG_DB_OUTPUT_PATH,
            ARG_DB_DROP_ARCHIVES,
            ARG_DB_TABLES,
            ARG_YES,
        ),
    ),
    ActionCommand(
        name="drop-archived",
        help="Drop archived tables created through the db clean command",
        func=lazy_load_command("airflow.cli.commands.db_command.drop_archived"),
        args=(ARG_DB_TABLES, ARG_YES),
    ),
)
CONNECTIONS_COMMANDS = (
    ActionCommand(
        name="get",