[FIX] website_mail_channel: message count
[FIX] website_mail_channel: message count

The message count on a mailing list looks incorrect since notifications
are counted but not displayed.

opw-691948

ygol/odoo,ygol/odoo,ygol/odoo,dfang/odoo,dfang/odoo,hip-odoo/odoo,dfang/odoo,hip-odoo/odoo,hip-odoo/odoo,dfang/odoo,ygol/odoo,hip-odoo/odoo,ygol/odoo,hip-odoo/odoo,dfang/odoo,ygol/odoo,hip-odoo/odoo,ygol/odoo,dfang/odoo