Scheduling based on dataset aliases

[Lee-W]

Related: #40039

What

In #40478, we introduce a new class DatasetAlias, which allows emitting DatasetEvents or creating Datasets in a task. This PR allows us to schedule a DAG run based on DatasetAlias.

Example

with DAG(dag_id="dataset-producer"):
    @task(outlets=[Dataset("example-alias")])
    def produce_dataset_events():
        pass

with DAG(dag_id="dataset-alias-producer"):
    @task(outlets=[DatasetAlias("example-alias")])
    def produce_dataset_events(*, outlet_events):
        outlet_events["example-alias"].add(Dataset("s3://bucket/my-task"))

with DAG(dag_id="dataset-consumer", schedule=Dataset("s3://bucket/my-task")):
    ...

with DAG(dag_id="dataset-alias-consumer", schedule=DatasetAlias("example-alias")):
    ...

In the example above, before the DAG "dataset-alias-producer" is executed, the dataset alias DatasetAlias("example-alias") is not yet resolved to Dataset("s3://bucket/my-task"). Consequently, completing the execution of the DAG "dataset-producer" will only trigger the DAG "dataset-consumer" and not the DAG "dataset-alias-consumer". However, upon triggering the DAG "dataset-alias-producer", the DatasetAlias("example-alias") will be resolved to Dataset("s3://bucket/my-task"), and it will produce a dataset event that triggers the DAG "dataset-consumer". At this point, DatasetAlias("example-alias") is resolved to Dataset("s3://bucket/my-task"). Therefore, completing the execution of either DAG "dataset-producer" or "dataset-alias-producer" will trigger both the DAG "dataset-consumer" and "dataset-alias-consumer".

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[Lee-W]

All the comments were addressed. Please let me know if anyone wants to take a deeper look. I'm planning on merging this one later today.