[Bug]: Support for Mandatory Item Variants in Subscription Billing Module [SubscriptionBilling]

[miljance]

Summary

1. Variant Code is now selectable when extending Subscription Customer Contract
2. Variant Code can be made visible on a Customer Contract Line Subpage and can be changed directly in the Contract Line
3. Similar to a sales document, Variant Code is rendered with a red star if Variant Code should be entered.
4. A test testing the update of a Service Object when a field is changed on a Customer Contract Line has been extended.

Work Item(s)

Fixes #4400
Fixes AB#604193

[miljance]

@anjajanic Can you do a code review please?

[pri-kise]

I couldn't see any check on the variant blocked property.
e.g. when a variant is selected.
Is this intentional?
I know that this feature is still new for the variant (https://github.com/microsoft/BusinessCentralApps/pull/351).

[miljance]

I couldn't see any check on the variant blocked property. e.g. when a variant is selected. Is this intentional? I know that this feature is still new for the variant (microsoft/BusinessCentralApps#351).

Thanks, I wasn't aware this change coming in. I guess I would like to have it aligned. I will have another round then.

[pri-kise]

I checked again some lines above and below your changes, since I was looking for the logic that updates the description with ItemVariant Translation (or the Description).
Maybe this code is already and I only don't see it.
Since this wasn't part of the original change, this don't need to be changed with this PR.
I'm only asking questions.