List Coupons

curl --request GET \
  --url https://api.withflex.com/v1/coupons \
  --header 'Authorization: Bearer <token>'

{
  "coupons": [
    {
      "coupon_id": "fcoup_1234567890",
      "amount_off": 123,
      "applies_to": {
        "products": [
          "<string>"
        ]
      },
      "duration": "<any>",
      "duration_in_months": 123,
      "metadata": {},
      "name": "<string>",
      "percent_off": 123,
      "max_redemptions": 123,
      "times_redeemed": 123,
      "valid": true,
      "created_at": "<string>",
      "test_mode": true
    }
  ]
}