### Description

After the release for Airflow 2.6.0 I was integrating some forms into our setup and was missing some options selections - and some nice features to make selections user friendly.

I'd like do contribute some few features into the user forms:
* A select box option where proposals are made but user is not limited to hard `enum` list (`enum` is restricting user input to only the options provided)
* A multi-option pick list (because sometimes a single selection is just not enough
* Labels so that technical values used to control the DAG are different from what is presented as option to user

### Use case/motivation

After the initial release of UI trigger forms, add more features (incrementially)

### Related issues

Relates or potentially has a conflict with #31299, so this should be merged before.

### Are you willing to submit a 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)

True,
            type="boolean",
            title="Please confirm",
            description="A On/Off selection with a proper description.",
        ),
        
        "date_time": Param(
            f"{datetime.date.today()}T{datetime.time(hour=12, minute=17, second=00)}+00:00",
            type="string",
            format="date-time",
            title="Date-Time Picker",
            description="Please select a date and time, use the button on the left for a pup-up calendar.",
        ),
        "date": Param(
            f"{datetime.date.today()}",
            type="string",
            format="date",
            title="Date Picker",
            description="Please select a date, use the button on the left for a pup-up calendar. "
            "See that here are no times!",
        ),
        "time": Param(
            f"{datetime.time(hour=12, minute=13, second=14)}",
            type=["string", "null"],
            format="time",
            title="Time Picker",
            description="Please select a time, use the button on the left for a pup-up tool.",
        ),