[FIX] mail: Avoid traceback on notification for some browsers
[FIX] mail: Avoid traceback on notification for some browsers

Before showing a chat notification, a check is performed to ensure that the browser does support
notifications. On browsers that do not support Notification (IE, android native,...), the check was wrong and
would eventually cause a traceback. This will no longer happen.

hip-odoo/odoo,microcom/odoo,ygol/odoo,sysadminmatmoz/OCB,bplancher/odoo,bplancher/odoo,sysadminmatmoz/OCB,Elico-Corp/odoo_OCB,storm-computers/odoo,laslabs/odoo,microcom/odoo,Elico-Corp/odoo_OCB,ygol/odoo,dfang/odoo,laslabs/odoo,storm-computers/odoo,bplancher/odoo,ygol/odoo,laslabs/odoo,ygol/odoo,bplancher/odoo,microcom/odoo,laslabs/odoo,laslabs/odoo,dfang/odoo,Elico-Corp/odoo_OCB,storm-computers/odoo,storm-computers/odoo,sysadminmatmoz/OCB,ygol/odoo,hip-odoo/odoo,ygol/odoo,sysadminmatmoz/OCB,Elico-Corp/odoo_OCB,hip-odoo/odoo,bplancher/odoo,Elico-Corp/odoo_OCB,ygol/odoo,hip-odoo/odoo,laslabs/odoo,storm-computers/odoo,sysadminmatmoz/OCB,bplancher/odoo,microcom/odoo,dfang/odoo,Elico-Corp/odoo_OCB,hip-odoo/odoo,sysadminmatmoz/OCB,hip-odoo/odoo,sysadminmatmoz/OCB,storm-computers/odoo,dfang/odoo,dfang/odoo,dfang/odoo,microcom/odoo,microcom/odoo