### 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)

"required_field": Param(
            "You can not trigger if no text is given here!",
            type="string",
            title="Required text field",
            description="This field is required. You can not submit without having text in here.",
        ),
        "optional_field": Param(
            "optional text, you can trigger also w/o text",
            type=["null", "string"],
            title="Optional text field",
            description_html="This field is optional. As field content is JSON schema validated you must "
            "allow the <code>null</code> type.",
        ),
        
        
        
        
        "checked_text": Param(
            "length-checked-field",
            type="string",
            title="Text field with length check",
            description_html="""This field is required. And you need to provide something between 10 and 30
            characters. See the
            <a href='https://json-schema.org/understanding-json-schema/reference/string.html'>
            JSON schema description (string)</a> in for more details""",
            minLength=10,
            maxLength=20,
            section="JSON Schema validation options",
        ),