[REV] delivery: remove rounding from delivery

This PR reverts https://github.com/odoo/odoo/pull/119912 and
https://github.com/odoo/odoo/pull/119380 because of rounding issues
with `float_round` method. The rounding should be added to the carriers
if it is needed in the future.
(e.g. https://github.com/odoo/enterprise/pull/40536

)

opw-3289042

closes odoo/odoo#120232

Signed-off-by: Tiffany Chang <tic@odoo.com>