### 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)

"x": 3,
        "text": "Hello World!",
        "flag": False,
        "a_simple_list": ["one", "two", "three", "actually one value is made per line"],
        
        
        
        "most_loved_number": Param(
            42,
            type="integer",
            title="You favorite number",
            description_html="""Everybody should have a favorite number. Not only math teachers.
            If you can not think of any at the moment please think of the 42 which is very famous because
            of the book
            <a href='https://en.wikipedia.org/wiki/Phrases_from_The_Hitchhiker%27s_Guide_to_the_Galaxy#
            The_Answer_to_the_Ultimate_Question_of_Life,_the_Universe,_and_Everything_is_42'>
            The Hitchhiker's Guide to the Galaxy</a>""",
        ),
        
        "pick_one": Param(
            "value 1",
            type="string",
            title="Select one Value",
            description="You can use JSON schema enum's to generate drop down selection boxes.",
            enum=[f"value {i}" for i in range(1, 42)],
        ),
        
        "bool": Param(