Show option description in Behaviours "preserve user input" flag

When user provided value is overridden by a Behaviour, a warning flag containing that old value is shown to the user, so that they can easily copy-paste or re-select their previous inputs.

Unfortunately for dropdown components (aka. {{select}}s), value that was provided to the user is option ID, not description.

The flag should present option description, so that users can easily re-select values.