Allow Deletion of Executed Network Changes

NetBrain currently prevents deletion of a Network Change record whenever it contains an executed Network Change node, and this restriction applies even to users who hold the Delete Network Change privilege and an administrative role. As a result, authorized users have no supported path to remove completed or no-longer-needed change records from the Network Change list. This enhancement would allow users with appropriate privileges to delete Network Change records that include executed nodes, or provide an explicit administrative override for this scenario. Enabling this capability would let teams maintain a clean and accurate change history without requiring manual database intervention to remove obsolete records.