[Backoffice] Throw generic error when create/edit product variant and unnecessary redirect to homepage

[VanCongBang]

In backoffice, when creating new Product or editing Product, when try to add new product variation, it has checked for GTIN & SKU exist in database or not.

But instead of stay in page and notify user, it redirect to home page, and throw generic error " UPDATE FAILED " -> make user don't know which error caused this problem.

Expect: Throw detail error that API respone , and stay in create/edit page and let user continue modify.

[nashtech-tuannguyenhuu1]