Retrieve product variants

curl --request GET \
  --url https://services.commercengine.dev/api/v1/x2yh61zw4k/storefront/catalog/products/{product_id}/variants \
  --header 'Authorization: Bearer <token>'

{
  "message": "Products retrieved successfully.",
  "success": true,
  "content": {
    "variants": [
      {
        "id": "<string>",
        "name": "<string>",
        "short_description": "<string>",
        "active": true,
        "stock_available": true,
        "on_subscription": true,
        "on_promotion": true,
        "associated_options": {},
        "metadata": [
          {
            "key": "<string>",
            "value": "<string>"
          }
        ],
        "sku": "<string>",
        "pricing": {
          "currency": "<string>",
          "tax_region": "<string>",
          "tax_type": "GST",
          "tax_rate": 123,
          "price_including_tax": false,
          "listing_price": 123,
          "selling_price": 123,
          "min_order_quantity": 123,
          "max_order_quantity": 123
        },
        "images": [
          {
            "title": "<string>",
            "alternate_text": "<string>",
            "sort_order": 123,
            "url_tiny": "<string>",
            "url_thumbnail": "<string>",
            "url_standard": "<string>",
            "url_zoom": "<string>"
          }
        ],
        "subscription": [
          {
            "subscription_plan": "<string>",
            "subscription_price": 123,
            "billing_interval": 123,
            "billing_frequency": "monthly",
            "billing_limit": 123,
            "fulfill_separately": false,
            "order_interval": 123,
            "order_frequency": "monthly",
            "order_limit": 123,
            "quantity": 123,
            "billing_trial_days": 123
          }
        ],
        "promotion": [
          {
            "type": "discount",
            "details": {
              "discount_type": "percent",
              "discount_percent": 10,
              "discount_amount": 150.65,
              "max_amount": 2500
            }
          }
        ],
        "shipping": {
          "is_free_shipping": false,
          "is_fixed_cost_shipping": false,
          "fixed_cost_shipping_price": 123,
          "shipping_price_including_tax": true,
          "availability_description": "<string>",
          "ships_internationally": true,
          "mid_code": "<string>",
          "country_of_origin": "India",
          "tax_region": "<string>",
          "tax_type": "<string>",
          "tax_rate": 123
        }
      }
    ]
  }
}