### Apache Airflow version

2.6.1

### What happened

When playing around with the form features as interoduced in AIP-50 and using the select list option via `enum` I realized that the default value will not be correctly picked when the form is loaded. Instead the first value always will be pre-selected.

### What you think should happen instead

Default value should be respected

### How to reproduce

Modify the `airflow/example_dags/example_params_ui_tutorial.py:68` and change the default to some other value. Load the form and see that `value 1` is still displayed on form load.

### Operating System

Ubuntu 20.04

### Versions of Apache Airflow Providers

not relevant

### Deployment

Official Apache Airflow Helm Chart

### Deployment details

not relevant

### Anything else

Workaround: Make your default currently top of the list.

### Are you willing to submit PR?

- [X] 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)

"checked_number": Param(
            100,
            type="number",
            title="Number field with value check",
            description_html="""This field is required. You need to provide any number between 64 and 128.
            See the <a href='https://json-schema.org/understanding-json-schema/reference/numeric.html'>
            JSON schema description (numbers)</a> in for more details""",
            minimum=64,
            maximum=128,
            section="JSON Schema validation options",
        ),
        
        
        "object": Param(
            {"key": "value"},
            type=["object", "null"],
            title="JSON entry field",
            section="Special advanced stuff with form fields",
        ),
        
        
        
        "hidden_secret_field": Param("constant value", const="constant value"),
        
        
        "color_picker": Param(
            "#FF8800",
            type="string",
            title="Pick a color",
            description_html="""This is a special HTML widget as custom implementation in the DAG code.