Validation for select fields with token option fails
Problem/Motivation
In #3421088: Allow tokens in "Entity: create new" for langcode and #3422936: Add "Use token" option to drop-down lists we've introduced #eca_token_select_option to allow "defined by token" in select fields. That option fails during form validation when saving a model.
Proposed resolution
Handle this option as a special case during form field validation.
Edited by drupalbot