Use case: a x2m (ex: attribute values) displayed in a x2m (ex: attributes on
product) using different fields in different views (ex: tags in product form view
and list in product attribute form view). When opening the x2m record (in a
wizard) then going back on the form view, the tags are empty because the
`display_name` value has been lost when fetching x2m for the second time.
In this case, the list `fieldsInfo` needs to be updated with the existing
(default for tags) one so all the fields will be correctly loaded.
Task 1916891
closesodoo/odoo#29598
Martin Geubelle
6bb4b6698d