Remove duplicate fields in tree views / kanban (outside of templates).
A field should not be present twice in a kanban view. If one of the nodes
has custom attributes behavior of other nodes is somehow unpredicatable.
Having field present only once gives a more coherent behavior. Xpaths
could also lead to weird results if fields are present several times.
Notably adding a field in the view preface instead of inside the view
template itself (see b63043e for example of fix).
An heuristic to detect duplicate fields will land soon in master. As this
commit targets a stable version only view fixes are provided.
Task ID-2329114
PR odoo/odoo#56946
X-original-commit: 90f8e9255fa46c408763346ed135d9e561ae7fd5
Victor Feyens
f9f2c561bd