Two new tests are added, one with valid customizations and another with
invalid customizations.
Invalid customizations will return one of two error types, depending on
where exactly the failures was generated.
When the openapi schema fails to validate a request, it will return
IMAGE-BUILDLER-30.
When the error occurs while converting the openapi customizations to the
blueprint types, it will have the IMAGE-BUILDER-35 type instead.
5a5e6d732c