### 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)

#
#
#
"""DAG demonstrating various options for a trigger form generated by DAG params.
The DAG attribute `params` is used to define a default dictionary of parameters which are usually passed
to the DAG and which are used to render a trigger form.
"""
from __future__ import annotations
import datetime
import json
from pathlib import Path
from airflow import DAG
from airflow.decorators import task
from airflow.exceptions import AirflowSkipException
from airflow.models.dagrun import DagRun
from airflow.models.param import Param
from airflow.models.taskinstance import TaskInstance
with DAG(
    dag_id=Path(__file__).stem,
    description=__doc__[0 : __doc__.find(".")],
    doc_md=__doc__,
    schedule=None,
    start_date=datetime.datetime(2022, 3, 4),
    catchup=False,
    tags=["example_ui"],
    params={