This commit restores the sheet layout in mass_mailing for consistency reasons. The chatter was extracted from the tab it was in and moved back on the right side. This commit also fixes an alignment problem when an alert is displayed and the alert was vertically bigger that the buttons of the status bar task-3355071 closes odoo/odoo#130616 Forward-port-of: https://github.com/odoo/odoo/pull/126646 Signed-off-by: Pierre Paridans (app) <app@odoo.com>