### Body

Currently when you use multiple-outputs in decorator and it gets None value, it crashes.

As explained in https://github.com/apache/airflow/issues/32553 and workaround for ShortCircuitOperator has been implemented here:  https://github.com/apache/airflow/pull/32569 

But a more complete fix for multiple-outputs handling None is needed. 

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
with dag_maker(session=session):
        @task_decorator
        def task1(arg):
            return ["x" * arg]
        @task_decorator(retry_delay=30)
        def task2(arg1, arg2):
            ...
        task2.partial(arg1=1).expand(arg2=task1.expand(arg=[1, 2]))
    run = dag_maker.create_dagrun()
    
    dec = run.task_instance_scheduling_decisions(session=session)
    assert [ti.task_id for ti in dec.schedulable_tis] == ["task1", "task1"]
    for ti in dec.schedulable_tis:
        ti.run(session=session)
        assert not isinstance(ti.task, MappedOperator)
        assert ti.task.retry_delay == timedelta(seconds=300)  
    
    dec = run.task_instance_scheduling_decisions(session=session)
    assert [ti.task_id for ti in dec.schedulable_tis] == ["task2", "task2"]
    for ti in dec.schedulable_tis:
        unmapped = ti.task.unmap((ti.get_template_context(session), session))
        assert unmapped.retry_delay == timedelta(seconds=30)
def test_mapped_render_template_fields(dag_maker, session):