[REV] crm: remove unnecessary sudo

Revert "[FIX] crm: allow regular salesman to convert and merge opportunities"
This reverts commit 24db93c0.

Indeed adding a sudo at the end of merge process is a strange way to fix
an unexplained issue about "similar emails". CRM code has been cleaned
since v14+ and flows should not gain random sudo trying to solve an
undefined problem.

closes odoo/odoo#75360

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