### 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)

session.query(TI)
                .filter(
                    TI.dag_id == self.dag_id,
                    TI.run_id == self.run_id,
                    tuple_in_condition((TI.task_id, TI.map_index), schedulable_ti_ids),
                )
                .update({TI.state: State.SCHEDULED}, synchronize_session=False)
            )
        
        if dummy_ti_ids:
            count += (
                session.query(TI)
                .filter(
                    TI.dag_id == self.dag_id,
                    TI.run_id == self.run_id,
                    TI.task_id.in_(dummy_ti_ids),
                )
                .update(
                    {
                        TI.state: State.SUCCESS,
                        TI.start_date: timezone.utcnow(),
                        TI.end_date: timezone.utcnow(),
                        TI.duration: 0,
                    },
                    synchronize_session=False,
                )
            )
        return count
    @provide_session
    def get_log_template(self, *, session: Session = NEW_SESSION) -> LogTemplate: