We are spammed by some accounts that don't have credits anymore. With this commit, when we try to send letters from the cron, whenever we meet the CREDIT_ERROR error_code, we stop trying to send the letter. task-2930455 closes odoo/odoo#103530 X-original-commit: f1fed40e2f853ecd9e5c24e0882c67f9505155c2 Signed-off-by: Florian Daloze (fda) <fda@odoo.com>