error in DataResponse should not trigger TemplateEngine reponse

[danielpoe]

If Data Response fails then the 500 error template is shown.

Expected: A json error format (?)

Example stack

2019-05-17T14:13:07.643+0200 ERROR web/result.go:386 json: unsupported type: ....
flamingo/flamingo/core/zap/logger.go:77
flamingo.me/flamingo/v3/framework/web.(*Responder).ServerError
flamingo/flamingo/framework/web/result.go:386
flamingo.me/flamingo/v3/framework/controller.(*Error).Error
flamingo/flamingo/framework/controller/error.go:28
flamingo.me/flamingo/v3/framework/web.(*handler).ServeHTTP
flamingo/flamingo/framework/web/handler.go:217
flamingo.me/flamingo/v3/framework/prefixrouter.(*FrontRouter).ServeHTTP
flamingo/flamingo/framework/prefixrouter/front_router.go:136