[Subscription Billing]Subscription Lines Deletion Fix

[miljance]

Summary

This pull request introduces improvements to the deletion logic for subscription headers and adds comprehensive tests to ensure correct handling of associated subscription lines. The main focus is to ensure that unassigned subscription lines are deleted when their header is deleted, while headers with assigned lines are protected from deletion.

Deletion logic improvements

• Added a missing SetRange("Subscription Contract No.") filter before deleting service commitments in table 8057 "Subscription Header" to ensure only relevant records are deleted.

Test coverage enhancements

• Added a test to verify that unassigned subscription lines are deleted when their subscription header is deleted in codeunit 148157 "Service Object Test".
• Added a test to ensure an error is raised when attempting to delete a subscription header with subscription lines assigned to a contract, protecting data integrity.

Work Item(s)

Fixes #6314

Fixes AB#620365