[Extensibility Request] Missing extensibility for dimensions in Subscription Line

Describe the issue

in table 8059 "Subscription Line", it would be helpful to make the creating of the dimensions extensible.

1. New Publisher in AddDefaultDimensionSources with
   OnAfterAddDefaultDimensions(Rec, DefaultDimSource, UseSources)

2. make the "SetDefaultDimensions" function usable from external code.

If the dimension creation will be refactored to be more like the standard dimension creation (like sales line), that would be helpful too.

We want to add a project relation to the subscription, with project dimensions. - and want to start the dimension creation validating the project no.

OnAfterGetCombinedDimensionSetID is there, but maybe a little bit to late, depending on the priorities for dimensions based on source code.

Expected behavior

• Creation of dimensions is available from 3rd party code
• new fields can be added as a source for dimension creation
• seeing standard patterns for creating dimensions also in subscription line

Steps to reproduce

https://github.com/microsoft/BCApps/blob/main/src/Apps/W1/Subscription%20Billing/App/Service%20Commitments/Tables/SubscriptionLine.Table.al

internal procedure SetDefaultDimensions(UseSource: Boolean)

-> Is Internal

internal procedure ApplyContractDimensions and
local procedure AddDefaultDimensionSources

are not offering a publisher to add dimension sources to the defaultdimSource-list

Additional context

if a refactoring using standard pattern should be planned, maybe a product developer from Microsoft has the better overview of this module to implement the necessary logic

I will provide a fix for a bug

• I will provide a fix for a bug

Start with src/Apps/W1/Subscription Billing/App/Service Commitments/Tables/SubscriptionLine.Table.al and read SetDefaultDimensions, ApplyContractDimensions, and AddDefaultDimensionSources. Compare the dimension-creation pattern used by the sales line, then determine how the requested publisher and external procedure access should fit. Done means third-party code can add dimension sources and initiate creation early enough to validate the project number.