This field widget is no longer used in form, list or kanban views,
so it hasn't been converted to owl. This commit removes its legacy
implementation from the registry, s.t. we ensure nobody use it
again. Moreover, we adapted a new view test using it to use another
field widget instead, to remove the dependency and ease the removal
that should happen soon.
closesodoo/odoo#101787
X-original-commit: 68cfd4b08bc9ab0305ae9033e42820370b52bdf3
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>