Multi-Select, Text Proposals and Value Labels forTrigger Forms

[jscheffl]

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?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct