Chore: Remove global bus variable (#50765)

* Chore: Remove global bus variable

* fix bus in tests

pkg/services/notifications/send_email_integration_test.go

@@ -5,7 +5,6 @@ import (
 	"io/ioutil"
 	"testing"
 
-	"github.com/grafana/grafana/pkg/bus"
 	"github.com/grafana/grafana/pkg/models"
 	"github.com/grafana/grafana/pkg/setting"
 
@@ -20,7 +19,7 @@ func TestEmailIntegrationTest(t *testing.T) {
 		setting.BuildVersion = "4.0.0"
 
 		ns := &NotificationService{}
-		ns.Bus = bus.New()
+		ns.Bus = newBus(t)
 		ns.Cfg = setting.NewCfg()
 		ns.Cfg.Smtp.Enabled = true
 		ns.Cfg.Smtp.TemplatesPatterns = []string{"emails/*.html", "emails/*.txt"}