[FIX] crm: lead probability too close to 100%

If you have some leads which are nearly always won or lost, you may
end with a probability which is either 0% or 100%.
These values indicate that the lead is lost or won, therefore we must
check the limit values.

opw-3413206

closes odoo/odoo#128237

Signed-off-by: Jérémy Hennecart (jeh) <jeh@odoo.com>