Ability to amend a subscription with no product via Salesforce

[Zuora-Community]

If customer has a subscription with no product in Zuora, when trying to create an Amendment Quote in Salesforce, an error will occur.

Attempt to de-reference a null object

Error is in expression '{!theOptions}' in component <zqu:selectproduct> in component zqu:selectproduct

An unexpected error has occurred. Your solution provider has been notified. (zqu)

Because the current subscription version in Zuora has no product, when an amendment quote is created, it checks for existing products and the validation fails.

We should allow customer to amend subscription with no product via Zuora Quotes as this is supported in Zuora UI.