Kanban and form archs aren't owl templates. Kanban archs define
a (historically) qweb template ("kanban-box") which is html + some
directives (e.g. t-esc, t-foreach...) and extra tags (field, widget).
Form view archs are html + some extra tags (e.g. group, notebook,
field, widget...).
With the conversion of those views to owl, a door was left open:
one *could* use owl directives (for instance, t-on-click) in archs.
However, we don't want people to do that, as it would tie the archs
in database with js implementation details, which will then limit
the evolution of the js framework.
This commit adds warning when such forbidden directives are detected.
In master, we'll raise errors.
Part-of: odoo/odoo#108221
Aaron Bohy
aa616d2880