This patch removes the `with_service` helper from the code base.
Instead, we can pass a block with actions directly to the `.call` method
of a service.
This simplifies how to use services:
- use `.call` without a block to run the service and get its result
object.
- use `.call` with a block of actions to run the service and execute
arbitrary code depending on the service outcome.
It also means a service is now “self-contained” and can be used anywhere
without having to include a helper or whatever.
This patch allows using an AR relation as a model in services without
fetching associated records. It will just check if the relation is empty
or not. In the former case, the execution will stop at that point, as
expected.
