[FIX] im_livechat: smiley feedback correspond to choice

When a user on website sends livechat feedbacks:

- Good -> send an average smiley 
- Average -> send ?? instead of smiley

This is because in e4a4ffb9 value of good () was changed from 10 to 5,
and value for average (

) was changed from 5 to 3, but it was not
reflected in one part of the code.

opw-2447246

closes odoo/odoo#65328

Signed-off-by: Nicolas Lempereur (nle) <nle@odoo.com>