[IMP] mail: Remove unused method
[IMP] mail: Remove unused method

Method was added at cf505c3 but not used, missing cleanup according to
xdo-odoo

closes odoo/odoo#42443

Signed-off-by: Martin Trigaux (mat) <cc7c5be316e48d137cbb549833b85d91034d799d@odoo.com>

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo