### 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)

task_instance,
                        )
                        session.query(TI).filter(
                            TI.dag_id == dag_id, TI.state == TaskInstanceState.SCHEDULED
                        ).update({TI.state: TaskInstanceState.FAILED}, synchronize_session="fetch")
                        continue
                    task_concurrency_limit: int | None = None
                    if serialized_dag.has_task(task_instance.task_id):
                        task_concurrency_limit = serialized_dag.get_task(
                            task_instance.task_id
                        ).max_active_tis_per_dag
                    if task_concurrency_limit is not None:
                        current_task_concurrency = task_concurrency_map[
                            (task_instance.dag_id, task_instance.task_id)
                        ]
                        if current_task_concurrency >= task_concurrency_limit:
                            self.log.info(
                                "Not executing %s since the task concurrency for"
                                " this task has been reached.",
                                task_instance,
                            )
                            starved_tasks.add((task_instance.dag_id, task_instance.task_id))
                            continue
                executable_tis.append(task_instance)
                open_slots -= task_instance.pool_slots
                dag_active_tasks_map[dag_id] += 1
                task_concurrency_map[(task_instance.dag_id, task_instance.task_id)] += 1
                pool_stats["open"] = open_slots
            is_done = executable_tis or len(task_instances_to_examine) < max_tis