Remove flex discount code from a subscription

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Which topic?

https://developer.adobe.com/vipmp/docs/flex-discounts/apis#remove-a-flexible-discount-from-a-subscription

### What's wrong with the content?

I'm testing this feature and I managed to add a discount code to the subscription, but when I tried to remove it, it didn't work, even though the request returned with a success status. Is it only possible to remove it after the subscription is renewed?
The response doesn't return the offerId in the JSON object. This also happens when updating the subscription.

### What changes do you propose?

_No response_

### Anything else that can help to cover this?

_No response_

Start with the linked remove-a-flexible-discount-from-a-subscription API documentation and compare its remove and update behavior with the reported responses. Determine whether the missing offerId and successful removal response reflect incorrect documentation or an API problem; done means the expected behavior and response are clearly documented or the issue is routed as an API defect.

Written by the indexing model from the issue text.