[FIX] web: pie chart
[FIX] web: pie chart

Mixing positive and negative values in a pie chart is not possible.
However, in this case, a crash occurs instead of displaying an error
message.

opw-786137

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo