[FIX] mail: fix broken multi _message_compose_with_view

Returning after first loop iteration has the sad side effect of
somehow breaking batch version of methods.

Oversight of odoo/odoo@0ea27f430c27716e9f995523f050ba70fa4befde

closes odoo/odoo#99574

Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>