[FIX] point_of_sale: fix order change on note change

[abichinger]

The return value of changesToOrder is missing a line inside the cancelled array, while updating the note of an existing order line. From the POV of a preperation tool, this makes it look like a new item has been added to the order.

https://github.com/user-attachments/assets/618263ac-0a61-42f2-b662-10e1ae63e39f

While recording the video I captured the following values from changesToOrder

// 1st output after the orderline was created
{
    "new": [
        {
            "uuid": "db47ade6-c8e1-47e1-8dcc-8c43ef67de8a",
            "name": "Coca-Cola",
            "product_id": 100,
            "attribute_value_ids": [],
            "quantity": 1,
            "note": "",
            "pos_categ_id": 10,
            "pos_categ_sequence": 0
        }
    ],
    "cancelled": []
}

// 2nd output after the note was added
{
    "new": [
        {
            "uuid": "db47ade6-c8e1-47e1-8dcc-8c43ef67de8a",
            "name": "Coca-Cola",
            "product_id": 100,
            "attribute_value_ids": [],
            "quantity": 1,
            "note": "Zero",
            "pos_categ_id": 10,
            "pos_categ_sequence": 0
        }
    ],
    "cancelled": []
}

I would expect the second output to look like this

{
    "new": [
        {
            "uuid": "db47ade6-c8e1-47e1-8dcc-8c43ef67de8a",
            "name": "Coca-Cola",
            "product_id": 100,
            "attribute_value_ids": [],
            "quantity": 1,
            "note": "Zero",
            "pos_categ_id": 10,
            "pos_categ_sequence": 0
        }
    ],
    "cancelled": [
        {
            "uuid": "db47ade6-c8e1-47e1-8dcc-8c43ef67de8a",
            "name": "Coca-Cola",
            "product_id": 100,
            "attribute_value_ids": [],
            "quantity": 1,
            "note": "",
            "pos_categ_id": 10,
            "pos_categ_sequence": 0
        }
    ]
}

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[robodoo]

[davidmonnom]

That's the expected behavior, we don't want to cancel and recreate but we want to add the note to the current line.