### Apache Airflow version

2.2.0b2 (beta snapshot)

### Operating System

ubuntu 20.04

### Versions of Apache Airflow Providers

n/a

### Deployment

Virtualenv installation

### Deployment details

pip install /path/to/airflow/src

### What happened

Given any DAG initialized with: `schedule_interval=None`

Run `airflow dags test mydagname $(date +%Y-%m-%d)` and get an error:

```
INFO - No run dates were found for the given dates and dag interval.
```

This behavior changed in https://github.com/apache/airflow/pull/15397, it used to trigger a backfill dagrun at the given date.

### What you expected to happen

I expected a backfill dagrun with the given date, regardless of whether it fit into the `schedule_interval`.

If AIP-39 made that an unrealistic expectation, then I'd hope for some way to define unscheduled dags which can still be tested from the command line (which, so far as I know, is the fastest way to iterate on a DAG.).

As it is, I keep changing `schedule_interval` back and forth depending on whether I want to iterate via `astro dev start` (which tolerates `None` but does superfluous work if the dag is scheduled) or via `airflow dags test ...` (which doesn't tolerate `None`).

### How to reproduce

Initialize a DAG with: `schedule_interval=None` and run it via `airflow dags test mydagname $(date +%Y-%m-%d)`

### Anything else

_No response_

### Are you willing to submit 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)

airflow/cli/commands/dag_command.py
dagbag = DagBag(process_subdir(args.subdir))
    AirflowConsole().print_as(
        data=sorted(dagbag.dags.values(), key=lambda d: d.dag_id),
        output=args.output,
        mapper=lambda x: {
            "dag_id": x.dag_id,
            "filepath": x.filepath,
            "owner": x.owner,
            "paused": x.get_is_paused(),
        },
    )
@cli_utils.action_logging
@suppress_logs_and_warning
def dag_report(args):
    """Displays dagbag stats at the command line"""
    dagbag = DagBag(process_subdir(args.subdir))
    AirflowConsole().print_as(
        data=dagbag.dagbag_stats,
        output=args.output,
        mapper=lambda x: {
            "file": x.file,
            "duration": x.duration,
            "dag_num": x.dag_num,
            "task_num": x.task_num,
            "dags": sorted(ast.literal_eval(x.dags)),
        },
    )
@cli_utils.action_logging
@suppress_logs_and_warning
def dag_list_jobs(args, dag=None):