Fix Update::getChat() for cases when a User banned and/or unbanned a bot

[alies-dev]

Fix Update::getChat() for cases when a User banned and/or unbanned a bot

This is a special case when chat_id exist in a payload, but message object doesn't. Example of payload when a User banned a bot:

{
    "update_id": 276740005,
    "my_chat_member": {
        "chat": {
            "id": 2000000,
            "first_name": "Firstname",
            "last_name": "Lastname",
            "type": "private"
        },
        "from": {
            "id": 2000000,
            "is_bot": false,
            "first_name": "Firstname",
            "last_name": "Lastname",
            "language_code": "en"
        },
        "date": 1656768003,
        "old_chat_member": {
            "user": {
                "id": 2000001,
                "is_bot": true,
                "first_name": "My Bot",
                "username": "MyBot"
            },
            "status": "member"
        },
        "new_chat_member": {
            "user": {
                "id": 2000001,
                "is_bot": true,
                "first_name": "My Bot",
                "username": "MyBot"
            },
            "status": "kicked",
            "until_date": 0
        }
    }
}

Example of bot unbanned event:

{
    "update_id": 276740005,
    "my_chat_member": {
        "chat": {
            "id": 2000000,
            "first_name": "Firstname",
            "last_name": "Lastname",
            "type": "private"
        },
        "from": {
            "id": 2000000,
            "is_bot": false,
            "first_name": "Firstname",
            "last_name": "Lastname",
            "language_code": "en"
        },
        "date": 1656768003,
        "old_chat_member": {
            "user": {
                "id": 2000001,
                "is_bot": true,
                "first_name": "My Bot",
                "username": "MyBot"
            },
            "status": "kicked",
            "until_date": 0
        },
        "new_chat_member": {
            "user": {
                "id": 2000001,
                "is_bot": true,
                "first_name": "My Bot",
                "username": "MyBot"
            },
            "status": "member"
        }
    }
}

[irazasyed]

This is a very good improvement. Appreciated. Thanks 👍🏻😊