Feature/64800 select custom field format at the index page of custom fields and project attributes

[ulferts]

Ticket

https://community.openproject.org/wp/64800

What are you trying to accomplish?

Move the field format selection from within the create form of a custom field to the buttons on the index action.

Merge checklist

• [ ] Added/updated tests
• [ ] Added/updated documentation in Lookbook (patterns, previews, etc)
• [ ] Tested major browsers (Chrome, Firefox, Edge, ...)