[FIX] website_mail_channel: adapt snippet option to new UI
[FIX] website_mail_channel: adapt snippet option to new UI

closes odoo/odoo#39062

X-original-commit: f097f07f95b7fc4a6acc84d7df1e3501fa555ec7
Signed-off-by: Quentin Smetz (qsm) <75b324bb495ac8d4f83496f7c52eda774af7ed7a@odoo.com>

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