### Description

A count of datasets that are currently registered/declared in an Airflow deployment.

### Use case/motivation

Would be nice to see how deployments are adopting datasets.

### Related issues

_No response_

### 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)

)
                dataset_event_filters = [
                    DagScheduleDatasetReference.dag_id == dag.dag_id,
                    DatasetEvent.timestamp <= exec_date,
                ]
                if previous_dag_run:
                    dataset_event_filters.append(DatasetEvent.timestamp > previous_dag_run.execution_date)
                dataset_events = (
                    session.query(DatasetEvent)
                    .join(
                        DagScheduleDatasetReference,
                        DatasetEvent.dataset_id == DagScheduleDatasetReference.dataset_id,
                    )
                    .join(DatasetEvent.source_dag_run)
                    .filter(*dataset_event_filters)
                    .all()
                )
                data_interval = dag.timetable.data_interval_for_events(exec_date, dataset_events)
                run_id = dag.timetable.generate_run_id(
                    run_type=DagRunType.DATASET_TRIGGERED,
                    logical_date=exec_date,
                    data_interval=data_interval,
                    session=session,
                    events=dataset_events,
                )
                dag_run = dag.create_dagrun(
                    run_id=run_id,
                    run_type=DagRunType.DATASET_TRIGGERED,
                    execution_date=exec_date,
                    data_interval=data_interval,