Change apply_on for remove discount in a subscription

[BillWilson]

According to the parameters description here, the ApplyOn is required when creating new discount.

And it works as expected when creating new discount with empty apply_on.

{
  "message": "discounts[apply_on][0] : cannot be blank",
  "type": "invalid_request",
  "api_error_code": "invalid_request",
  "param": "discounts[apply_on][0]",
  "error_code": "param_should_not_be_blank",
  "error_msg": "cannot be blank",
  "error_param": "discounts[apply_on][0]",
  "http_status_code": 400
}

But when I try to delete a discount from subscription.
I always got this message unless I remove the key apply_on from the request payload.

{
  "message": "discounts[apply_on][0] : should not be sent when operation type is REMOVE",
  "type": "invalid_request",
  "api_error_code": "invalid_request",
  "param": "discounts[apply_on][0]",
  "error_code": "param_should_not_be_sent",
  "error_msg": "should not be sent when operation type is REMOVE",
  "error_param": "discounts[apply_on][0]",
  "http_status_code": 400
}

chargebee-go/models/subscription/subscription.go

Lines 864 to 865 in 5db10ca

	type UpdateForItemsDiscountParams struct {
	ApplyOn enum.ApplyOn `json:"apply_on"`