### 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.
"airflow connections export /tmp/connections.json\n"
            "The --file-format parameter can be used to control the file format. E.g., "
            "the default format is JSON in STDOUT mode, which can be overridden using: \n"
            "airflow connections export - --file-format yaml\n"
            "The --file-format parameter can also be used for the files, for example:\n"
            "airflow connections export /tmp/connections --file-format json.\n"
            "When exporting in `env` file format, you control whether URI format or JSON format "
            "is used to serialize the connection by passing `uri` or `json` with option "
            "`--serialization-format`.\n"
        ),
        func=lazy_load_command("airflow.cli.commands.connection_command.connections_export"),
        args=(
            ARG_CONN_EXPORT,
            ARG_CONN_EXPORT_FORMAT,
            ARG_CONN_EXPORT_FILE_FORMAT,
            ARG_CONN_SERIALIZATION_FORMAT,
            ARG_VERBOSE,
        ),
    ),
    ActionCommand(
        name="import",
        help="Import connections from a file",
        description=(
            "Connections can be imported from the output of the export command.\n"
            "The filetype must by json, yaml or env and will be automatically inferred."
        ),
        func=lazy_load_command("airflow.cli.commands.connection_command.connections_import"),
        args=(
            ARG_CONN_IMPORT,
            ARG_CONN_OVERWRITE,