Editable field with unlimited values doesn't work as expected

Problem/Motivation

For fields of unlimited values 'Add another item' button gets added as text to the input box rather than showing as a button resulting in an extra entry being added on update.

Steps to reproduce

Add a text field
Set values to unlimited
Set the field form display as editable field
When viewing the editable field the button 'Add another item' is included in the last empty input box.
On updating it creates the entry 'Add another item'
Deleting 'Add another item' still adds it

Proposed resolution

Make the add another item a button, like in the backend.

Remaining tasks

User interface changes

API changes

Data model changes