Alerting: fgac for notification policies and contact points (#46939) (#47406)

* add FGAC actions for silences table

* redirect users without permissions

* add permissions checks to routes

* add fgac to notifications and contact points

* fgac for notification policies

* fix mute timing authorization

* use consistent naming for checking grafana alertmanager

* tests for fgac in contact points and notification policies

* bump up timeout on rule editor test

* use new permissions util

* break out route evaluation into util

* Remove test timeout

* Change permissions for the alert-notifiers endpoint

* Use signed in handler for alert-notifiers when unified alerting enabled

Co-authored-by: Konrad Lalik <konrad.lalik@grafana.com>
(cherry picked from commit 49505b9a3b)

Co-authored-by: Nathan Rodman <nathanrodman@gmail.com>

pkg/api/api.go

@@ -14,6 +14,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/dashboards"
 	"github.com/grafana/grafana/pkg/services/datasources"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
+	"github.com/grafana/grafana/pkg/web"
 )
 
 var plog = log.New("api")
@@ -417,7 +418,14 @@ func (hs *HTTPServer) registerRoutes() {
 			alertsRoute.Get("/states-for-dashboard", routing.Wrap(hs.GetAlertStatesForDashboard))
 		})
 
-		apiRoute.Get("/alert-notifiers", reqEditorRole, routing.Wrap(
+		var notifiersAuthHandler web.Handler
+		if hs.Cfg.UnifiedAlerting.IsEnabled() {
+			notifiersAuthHandler = reqSignedIn
+		} else {
+			notifiersAuthHandler = reqEditorRole
+		}
+
+		apiRoute.Get("/alert-notifiers", notifiersAuthHandler, routing.Wrap(
 			hs.GetAlertNotifiers(hs.Cfg.UnifiedAlerting.IsEnabled())),
 		)