### 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_IGNORE_DEPENDS_ON_PAST = Arg(
    ("-I", "--ignore-depends-on-past"),
    help="Deprecated -- use `--depends-on-past ignore` instead. "
    "Ignore depends_on_past dependencies (but respect upstream dependencies)",
    action="store_true",
)
ARG_DEPENDS_ON_PAST = Arg(
    ("-d", "--depends-on-past"),
    help="Determine how Airflow should deal with past dependencies. The default action is `check`, Airflow "
    "will check if the past dependencies are met for the tasks having `depends_on_past=True` before run "
    "them, if `ignore` is provided, the past dependencies will be ignored, if `wait` is provided and "
    "`depends_on_past=True`, Airflow will wait the past dependencies until they are met before running or "
    "skipping the task",
    choices={"check", "ignore", "wait"},
    default="check",
)
ARG_SHIP_DAG = Arg(
    ("--ship-dag",), help="Pickles (serializes) the DAG and ships it to the worker", action="store_true"
)
ARG_PICKLE = Arg(("-p", "--pickle"), help="Serialized pickle object of the entire dag (used internally)")
ARG_JOB_ID = Arg(("-j", "--job-id"), help=argparse.SUPPRESS)
ARG_CFG_PATH = Arg(("--cfg-path",), help="Path to config file to use instead of airflow.cfg")
ARG_MAP_INDEX = Arg(("--map-index",), type=int, default=-1, help="Mapped task index")
ARG_READ_FROM_DB = Arg(("--read-from-db",), help="Read dag from DB instead of dag file", action="store_true")
ARG_MIGRATION_TIMEOUT = Arg(
    ("-t", "--migration-wait-timeout"),
    help="timeout to wait for db to migrate ",
    type=int,
    default=60,
)