### 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)

if next(task.iter_mapped_dependants(), None) is None:  
            return
        
        
        
        
        if isinstance(task, MappedOperator):
            return
        if value is None:
            raise XComForMappingNotPushed()
        if not _is_mappable_value(value):
            raise UnmappableXComTypePushed(value)
        task_map = TaskMap.from_task_instance_xcom(self, value)
        max_map_length = conf.getint("core", "max_map_length", fallback=1024)
        if task_map.length > max_map_length:
            raise UnmappableXComLengthPushed(value, max_map_length)
        session.merge(task_map)
    @provide_session
    def xcom_push(
        self,
        key: str,
        value: Any,
        execution_date: datetime | None = None,
        session: Session = NEW_SESSION,