[FIX] sale_coupon: move all discounts to the end of the sale_order

update to this PR[1]

BUG:
some discounts are still displayed on the middle of the order

FIX:
move all discounts to the end

[1]:https://github.com/odoo/odoo/pull/102700


opw-2985632

closes odoo/odoo#106508

X-original-commit: af8cc475
Signed-off-by: William Braeckman (wbr) <wbr@odoo.com>