### Description

expanding tasks in batches to allow mapped tasks spawn more than 1024 processes.

### Use case/motivation

Maximum length of a list is limited to 1024 by `max_map_length (AIRFLOW__CORE__MAX_MAP_LENGTH)`.
during scheduling of the new tasks, an UPDATE query is ran that tries to set all the new tasks at once.  Increasing `max_map_length` more than 4K makes airflow scheduler completely unresponsive.

Also, Postgres throws `stack depth limit exceeded` error which can be fixed by updating to a newer version and setting `max_stack_depth` higher. But it doesn't really matter because airflow scheduler freezes up.
 
As a workaround, I split the dag runs into subdag runs which works but it would be much nicer if we didn't have to worry about exceeding  `max_map_length`. 

### Related issues

It was discussed here:
[Increasing 'max_map_length' leads to SQL 'max_stack_depth' error with 5000 dags to be spawned #28478](https://github.com/apache/airflow/discussions/28478)

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

self._run_scheduler_loop()
            if self.processor_agent:
                
                self.processor_agent.terminate()
                
                
                
                if self.processor_agent.all_files_processed:
                    self.log.info(
                        "Deactivating DAGs that haven't been touched since %s", execute_start_time.isoformat()
                    )
                    DAG.deactivate_stale_dags(execute_start_time)
            settings.Session.remove()  
        except Exception:
            self.log.exception("Exception when executing SchedulerJob._run_scheduler_loop")
            raise
        finally:
            try:
                self.job.executor.end()
            except Exception:
                self.log.exception("Exception when executing Executor.end")
            if self.processor_agent:
                try:
                    self.processor_agent.end()
                except Exception:
                    self.log.exception("Exception when executing DagFileProcessorAgent.end")
            self.log.info("Exited execute loop")
        return None
    @provide_session
    def _update_dag_run_state_for_paused_dags(self, session: Session = NEW_SESSION) -> None: