[FIX] payment_stripe: tracebacks
[FIX] payment_stripe: tracebacks

Tracebacks due to key not present in dict, and inconsistent return of
the method.

hip-odoo/odoo,ygol/odoo,dfang/odoo,ygol/odoo,dfang/odoo,hip-odoo/odoo,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,dfang/odoo,dfang/odoo,ygol/odoo,ygol/odoo,dfang/odoo,hip-odoo/odoo,dfang/odoo,ygol/odoo