### 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.
help="Set the number of runs to execute before exiting",
)
ARG_DO_PICKLE = Arg(
    ("-p", "--do-pickle"),
    default=False,
    help=(
        "Attempt to pickle the DAG object to send over "
        "to the workers, instead of letting workers run their version "
        "of the code"
    ),
    action="store_true",
)
ARG_WITHOUT_MINGLE = Arg(
    ("--without-mingle",),
    default=False,
    help="Don't synchronize with other workers at start-up",
    action="store_true",
)
ARG_WITHOUT_GOSSIP = Arg(
    ("--without-gossip",),
    default=False,
    help="Don't subscribe to other workers events",
    action="store_true",
)
ARG_TASK_PARAMS = Arg(("-t", "--task-params"), help="Sends a JSON params dict to the task")
ARG_POST_MORTEM = Arg(
    ("-m", "--post-mortem"), action="store_true", help="Open debugger on uncaught exception"
)
ARG_ENV_VARS = Arg(
    ("--env-vars",),