Add support to get the Checklist from an Action.

In case when an Action is for instance of type "updateChecklist", it is not
related to a Card, but a Checklist, i.e.:

{
    ....,
    "data": {
        "board": {
            "id": "123456...."
        },
        "checklist": {
            "id": "ABCDE.....",
            "name": "Checklist name"
        },
        ...
    },
    "type": "updateChecklist",
    ...
}
Correct the value for Action.TYPE.UPDATE_LIST

See https://trello.com/docs/api/card/#card