Why not mark inactive DAGs in the main scheduler loop?

[Dan Davydov]

I see some PRs creating endpoints to delete DAGs and other things related
to manually deleting DAGs from the DB, but is there a good reason why we
can't just move the deactivating DAG logic into the main scheduler loop?

The scheduler already has some code like this, but it only runs when the
Scheduler terminates:
      if all_files_processed:
            self.log.info(
                "Deactivating DAGs that haven't been touched since %s",
                execute_start_time.isoformat()
            )
            models.DAG.deactivate_stale_dags(execute_start_time)