### Apache Airflow version

2.7.1

### What happened

120 DAGs broke when I updated to Airflow 2.7.1. I had to revert to 2.7.0 again, so the tests below are from a local deployment.

The error message is the same for all DAGs:

```python
Broken DAG: [/opt/airflow/dags/dag-name.py] Traceback (most recent call last):
  File "/home/airflow/.local/lib/python3.11/site-packages/airflow/models/dag.py", line 640, in __init__
    self.validate_schedule_and_params()
  File "/home/airflow/.local/lib/python3.11/site-packages/airflow/models/dag.py", line 3289, in validate_schedule_and_params
    raise AirflowException(
airflow.exceptions.AirflowException: DAG Schedule must be None, if there are any required params without default values
```

After testing, I found that if I change the blob_prefix param to "" instead of None, the DAG imports successfully. I have various other params which are None that I will probably need to assign default values for (in reality, the function which Airflow runs handles cases if the value is None, but I guess I need to add a default in the DAG). All 120 DAGs with errors had a field like this in the "params" dictionary I pass to Airflow params.

```python
params = {
    "exclude_pattern": "*errors*",
    "blob_prefix": None,
```

### What you think should happen instead

These are legacy DAGs which have run for a long time without changes (old Airflow instance), so I did not expect an upgrade to break them. 

### How to reproduce

I believe the root cause is passing a param with the value None to the DAG params:

```python
params = {
  subfolder=None,
  conn_id="gcs_conn_id",
}

@dag(
    dag_id="dag-example",
    start_date=datetime(2023, 2, 2, tz="America/New_York"),
    schedule="41 2 * * *",
    params=params,
)
```

### Operating System

Ubuntu 22.04

### Versions of Apache Airflow Providers

Providers info
apache-airflow-providers-celery          | 3.3.3 
apache-airflow-providers-common-sql      | 1.7.1 
apache-airflow-providers-docker          | 3.7.4 
apache-airflow-providers-ftp             | 3.5.1 
apache-airflow-providers-google          | 10.7.0
apache-airflow-providers-http            | 4.5.1 
apache-airflow-providers-imap            | 3.3.1 
apache-airflow-providers-microsoft-azure | 6.3.0 
apache-airflow-providers-mysql           | 5.3.0 
apache-airflow-providers-odbc            | 4.0.0 
apache-airflow-providers-openlineage     | 1.0.2 
apache-airflow-providers-postgres        | 5.6.0 
apache-airflow-providers-redis           | 3.3.1 
apache-airflow-providers-sftp            | 4.6.0 
apache-airflow-providers-sqlite          | 3.4.3 
apache-airflow-providers-ssh             | 3.7.2 

### Deployment

Other Docker-based deployment

### Deployment details

Docker Swarm using docker stack deploy

### Anything else

DAGs fail to import when deployed on 2.7.1

### 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)

here and `'depends_on_past': False` in the operator's call
        `default_args`, the actual value will be `False`.
    :param params: a dictionary of DAG level parameters that are made
        accessible in templates, namespaced under `params`. These
        params can be overridden at the task level.
    :param max_active_tasks: the number of task instances allowed to run
        concurrently
    :param max_active_runs: maximum number of active DAG runs, beyond this
        number of DAG runs in a running state, the scheduler won't create
        new active DAG runs
    :param dagrun_timeout: specify how long a DagRun should be up before
        timing out / failing, so that new DagRuns can be created.
    :param sla_miss_callback: specify a function or list of functions to call when reporting SLA
        timeouts. See :ref:`sla_miss_callback<concepts:sla_miss_callback>` for
        more information about the function signature and parameters that are
        passed to the callback.
    :param default_view: Specify DAG default view (grid, graph, duration,
                                                   gantt, landing_times), default grid
    :param orientation: Specify DAG orientation in graph view (LR, TB, RL, BT), default LR
    :param catchup: Perform scheduler catchup (or only run latest)? Defaults to True
    :param on_failure_callback: A function or list of functions to be called when a DagRun of this dag fails.
        A context dictionary is passed as a single parameter to this function.
    :param on_success_callback: Much like the ``on_failure_callback`` except
        that it is executed when the dag succeeds.
    :param access_control: Specify optional DAG-level actions, e.g.,
        "{'role1': {'can_read'}, 'role2': {'can_read', 'can_edit', 'can_delete'}}"
    :param is_paused_upon_creation: Specifies if the dag is paused when created for the first time.
        If the dag exists already, this flag will be ignored. If this optional parameter
        is not specified, the global config setting will be used.
    :param jinja_environment_kwargs: additional configuration options to be passed to Jinja