### 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)

yield ti
        tis = list(_filter_tis_and_exclude_removed(self.get_dag(), tis))
        unfinished_tis = [t for t in tis if t.state in State.unfinished]
        finished_tis = [t for t in tis if t.state in State.finished]
        if unfinished_tis:
            schedulable_tis = [ut for ut in unfinished_tis if ut.state in SCHEDULEABLE_STATES]
            self.log.debug("number of scheduleable tasks for %s: %s task(s)", self, len(schedulable_tis))
            schedulable_tis, changed_tis, expansion_happened = self._get_ready_tis(
                schedulable_tis,
                finished_tis,
                session=session,
            )
            
            
            if expansion_happened:
                changed_tis = True
                new_unfinished_tis = [t for t in unfinished_tis if t.state in State.unfinished]
                finished_tis.extend(t for t in unfinished_tis if t.state in State.finished)
                unfinished_tis = new_unfinished_tis
        else:
            schedulable_tis = []
            changed_tis = False
        return TISchedulingDecision(
            tis=tis,
            schedulable_tis=schedulable_tis,
            changed_tis=changed_tis,
            unfinished_tis=unfinished_tis,
            finished_tis=finished_tis,
        )
    def notify_dagrun_state_changed(self, msg: str = ""):