Purpose of this task is to prevent merging of opportunities when a regular (non super) user selects more than five records. This commit limits total number of recorrds to be merged, up to maximum five leads / opportunities for non superuser environment, and raises a UserError otherwise explaining the threshold limit. closes odoo/odoo#55024 Task-id: 2256126 X-original-commit: c25d7654f250c888cea84c20af16b2a32cc5b365 Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>