BUG: Missing item.discount property at GA4 purchase event

[badz0]

Describe the bug
When sending Order completed event with item.discount the discount is missing in GA4 debug view.

To Reproduce
Send Order completed event with products containing discount.

Expected behavior
discount property should be delivered to GA4

Screenshots

Additional context
Rudderstack payload

"products": [
    {
        "brand": "Paintbox Yarns",
        "category": "Yarns",
        "coupon": "10% off - DISCOUNT DESCRIPTION",
        "discount": 0.18,
        "name": "Paintbox Yarns Simply DK",
        "price": 1.62,
        "product_id": "0ba5ea3b-6c20-4217-a6f9-770ac7397978",
        "quantity": 1,
        "sku": "10116876",
        "variant": 21841,
    }
],

[contributor-support]

Thanks for opening this issue! We'll get back to you shortly. If it is a bug, please make sure to add steps to reproduce the issue.