### 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.
description=(
            "Drop all serialized dags from the metadata DB. This will cause all DAGs to be reserialized "
            "from the DagBag folder. This can be helpful if your serialized DAGs get out of sync with the "
            "version of Airflow that you are running."
        ),
        func=lazy_load_command("airflow.cli.commands.dag_command.dag_reserialize"),
        args=(
            ARG_CLEAR_ONLY,
            ARG_SUBDIR,
            ARG_VERBOSE,
        ),
    ),
)
TASKS_COMMANDS = (
    ActionCommand(
        name="list",
        help="List the tasks within a DAG",
        func=lazy_load_command("airflow.cli.commands.task_command.task_list"),
        args=(ARG_DAG_ID, ARG_TREE, ARG_SUBDIR, ARG_VERBOSE),
    ),
    ActionCommand(
        name="clear",
        help="Clear a set of task instance, as if they never ran",
        func=lazy_load_command("airflow.cli.commands.task_command.task_clear"),
        args=(
            ARG_DAG_ID,
            ARG_TASK_REGEX,
            ARG_START_DATE,
            ARG_END_DATE,
            ARG_SUBDIR,