We need to make independent_mapping_rules rolling update always enabled for services acting ad products.

Nowadays, whenever a service "acts as product", we are neither showing the "Mapping Rules" block in the proxy configuration form, nor enabling independent mapping rules. We need to reenable editing of product-level Mapping Rules.

For consistency to how we show backend API Mapping Rules, the product-level Mapping Rules show appear in the UI like they when the account is using independent_mapping_rules, as separate option in the menu under "API > Integration".