Support "half_width_on_mobile" for KP

[g123k]

Hi everyone!

The API for knowledge panels now send an attribute half_width_on_mobile for the layout needed by smooth-app:

Eg: https://world.openfoodfacts.org/api/v3/product/737628064502.json?fields=knowledge_panels

"nutrient_level_fat": {
                "elements": [
                    {
                        "element_type": "text",
                        "text_element": {
                            "html": "\n<b>What you need to know</b>\n<ul>\n<li>A high consumption of fat, especially saturated fats, can raise cholesterol, which increases the risk of heart diseases.</li>\n</ul>\n<br>\n<b>Recommendation</b>:\n<b>Limit the consumption of fat and saturated fat</b>\n<ul>\n<li>Choose products with lower fat and saturated fat content.</li>\n</ul>\n",
                            "type": "summary"
                        }
                    },
                    {
                        "element_type": "text",
                        "text_element": {
                            "html": "\n",
                            "source_language": "en",
                            "source_text": "National Health Service UK (NHS) - Fat: the facts",
                            "source_url": "https://www.nhs.uk/live-well/eat-well/food-types/different-fats-nutrition/",
                            "type": "summary"
                        }
                    }
                ],
                "evaluation": "average",
                "half_width_on_mobile": true,
                "level": "info",
                "size": "small",
                "title_element": {
                    "icon_size": "small",
                    "icon_url": "https://static.openfoodfacts.org/images/misc/moderate.svg",
                    "name": "Fat",
                    "title": "Fat in moderate quantity (7.69%)",
                    "type": "percentage",
                    "value": 7.69
                },
                "topics": [
                    "health"
                ]
            }