It is not possible to preview service discovery like it is with accounts and assets.
Service discovery is configured as part of account discovery for Windows assets to discover Windows services and tasks.
More information can be found in the Administration Guide.
Services can only be ignored and not deleted because if there was an option to delete them then they would be rediscovered every time discovery runs.
Ignoring a service is like adding it to an exclusion list.
Services are deleted once the account or asset they are associated with is deleted as well.