### 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=(
        "if set, the backfill will auto-rerun "
        "all the failed tasks for the backfill date range "
        "instead of throwing exceptions"
    ),
    action="store_true",
)
ARG_CONTINUE_ON_FAILURES = Arg(
    ("--continue-on-failures",),
    help=("if set, the backfill will keep going even if some of the tasks failed"),
    action="store_true",
)
ARG_DISABLE_RETRY = Arg(
    ("--disable-retry",),
    help=("if set, the backfill will set tasks as failed without retrying."),
    action="store_true",
)
ARG_RUN_BACKWARDS = Arg(
    (
        "-B",
        "--run-backwards",
    ),
    help=(
        "if set, the backfill will run tasks from the most "
        "recent day first.  if there are tasks that depend_on_past "
        "this option will throw an exception"
    ),
    action="store_true",
)
ARG_TREAT_DAG_AS_REGEX = Arg(