### 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)

import warnings
from collections import defaultdict
from datetime import datetime, timedelta
from pathlib import Path
from typing import TYPE_CHECKING, Collection, DefaultDict, Iterator
from sqlalchemy import and_, func, not_, or_, text
from sqlalchemy.exc import OperationalError
from sqlalchemy.orm import load_only, selectinload
from sqlalchemy.orm.session import Session, make_transient
from sqlalchemy.sql import expression
from airflow import settings
from airflow.callbacks.callback_requests import DagCallbackRequest, SlaCallbackRequest, TaskCallbackRequest
from airflow.callbacks.pipe_callback_sink import PipeCallbackSink
from airflow.configuration import conf
from airflow.exceptions import RemovedInAirflow3Warning
from airflow.executors.executor_loader import ExecutorLoader
from airflow.jobs.base_job import BaseJob
from airflow.models.dag import DAG, DagModel
from airflow.models.dagbag import DagBag
from airflow.models.dagrun import DagRun
from airflow.models.dataset import (
    DagScheduleDatasetReference,
    DatasetDagRunQueue,
    DatasetEvent,
    DatasetModel,
    TaskOutletDatasetReference,
)
from airflow.models.serialized_dag import SerializedDagModel
from airflow.models.taskinstance import SimpleTaskInstance, TaskInstance, TaskInstanceKey
from airflow.stats import Stats