Have a list view (new RelationalModel inside a WOWL list view) that has
a legacy many2many tags field in its arch.
Try to add or remove some records from that many2many.
Before this commit, there was a crash, because the legacy field wrapper
doesn't use the model the right way for that case.
After this commit, there is no crash.
closesodoo/odoo#99431
Signed-off-by: Georis François (fge) <fge@odoo.com>