### 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 env var in both parsing time and runtime for each of entry supplied in a JSON dict",
    type=json.loads,
)
ARG_CONN_ID = Arg(("conn_id",), help="Connection id, required to get/add/delete/test a connection", type=str)
ARG_CONN_ID_FILTER = Arg(
    ("--conn-id",), help="If passed, only items with the specified connection ID will be displayed", type=str
)
ARG_CONN_URI = Arg(
    ("--conn-uri",), help="Connection URI, required to add a connection without conn_type", type=str
)
ARG_CONN_JSON = Arg(
    ("--conn-json",), help="Connection JSON, required to add a connection using JSON representation", type=str
)
ARG_CONN_TYPE = Arg(
    ("--conn-type",), help="Connection type, required to add a connection without conn_uri", type=str
)
ARG_CONN_DESCRIPTION = Arg(
    ("--conn-description",), help="Connection description, optional when adding a connection", type=str
)
ARG_CONN_HOST = Arg(("--conn-host",), help="Connection host, optional when adding a connection", type=str)
ARG_CONN_LOGIN = Arg(("--conn-login",), help="Connection login, optional when adding a connection", type=str)
ARG_CONN_PASSWORD = Arg(
    ("--conn-password",), help="Connection password, optional when adding a connection", type=str
)
ARG_CONN_SCHEMA = Arg(
    ("--conn-schema",), help="Connection schema, optional when adding a connection", type=str
)
ARG_CONN_PORT = Arg(("--conn-port",), help="Connection port, optional when adding a connection", type=str)
ARG_CONN_EXTRA = Arg(
    ("--conn-extra",), help="Connection `Extra` field, optional when adding a connection", type=str