### 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)

"""Fetch rendered template fields from DB"""
        from airflow.models.renderedtifields import RenderedTaskInstanceFields
        rendered_k8s_spec = RenderedTaskInstanceFields.get_k8s_pod_yaml(self, session=session)
        if not rendered_k8s_spec:
            try:
                rendered_k8s_spec = self.render_k8s_pod_yaml()
            except (TemplateAssertionError, UndefinedError) as e:
                raise AirflowException(f"Unable to render a k8s spec for this taskinstance: {e}") from e
        return rendered_k8s_spec
    def overwrite_params_with_dag_run_conf(self, params, dag_run):
        """Overwrite Task Params with DagRun.conf"""
        if dag_run and dag_run.conf:
            self.log.debug("Updating task params (%s) with DagRun.conf (%s)", params, dag_run.conf)
            params.update(dag_run.conf)
    def render_templates(self, context: Context | None = None) -> Operator:
        """Render templates in the operator fields.
        If the task was originally mapped, this may replace ``self.task`` with
        the unmapped, fully rendered BaseOperator. The original ``self.task``
        before replacement is returned.
        """
        if not context:
            context = self.get_template_context()
        original_task = self.task
        
        
        
        
        original_task.render_template_fields(context)
        return original_task
    def render_k8s_pod_yaml(self) -> dict | None: