Consistently Use Simulator flag Helper methods in Campaign configurations
This merge request builds on !61433 (merged) and !61435 (merged) to make the configuration of simulation outside ISF behave in the same way in legacy and CA-based configuration. It is necessary to update this as some workflows, such as forward detector simulation are not supported inside ISF.
A new ART test is added to test this updated configuration syntax. The other jobs in SimCoreTests will be updated in a follow-up MR.