Display field in two groups to display in four column.
Plus, email_from is used to 'Allow communication with a customer without
creating a partner'.
Since this field is not very useful, it is best to hide it to clean the UI.
Something was already done at aa33c81535
task-54027
closes odoo/odoo#22845
Signed-off-by: Jérémy Kersten (jke) <jke@openerp.com>