Chore: reduces barrel files part II (#107688)

* Chore: reduce barrel files

* chore: fixes unit test

* Chore: reduces barrel files part II

* chore: fix import sorting

apps/alerting/notifications/pkg/apis/alerting_manifest.go

@@ -14,8 +14,6 @@ import (
 	v0alpha1 "github.com/grafana/grafana/apps/alerting/notifications/pkg/apis/alerting/v0alpha1"
 )
 
-var ()
-
 var appManifestData = app.ManifestData{
 	AppName: "alerting",
 	Group:   "notifications.alerting.grafana.app",

apps/dashboard/pkg/apis/dashboard_manifest.go

@@ -16,8 +16,6 @@ import (
 	v2alpha1 "github.com/grafana/grafana/apps/dashboard/pkg/apis/dashboard/v2alpha1"
 )
 
-var ()
-
 var appManifestData = app.ManifestData{
 	AppName: "dashboard",
 	Group:   "dashboard.grafana.app",

apps/folder/pkg/apis/folder_manifest.go

@@ -14,8 +14,6 @@ import (
 	v1beta1 "github.com/grafana/grafana/apps/folder/pkg/apis/folder/v1beta1"
 )
 
-var ()
-
 var appManifestData = app.ManifestData{
 	AppName: "folder",
 	Group:   "folder.grafana.app",