Alerting: Use alerting.GrafanaAlertmanager instead of initialising Alertmanager components directly (#61230)

* Alerting: Use `alerting.GrafanaAlertmanager` instead of initialising Alertmanager components directly

pkg/services/ngalert/api/api_alertmanager.go

@@ -288,7 +288,7 @@ func (srv AlertmanagerSrv) RoutePostTestReceivers(c *models.ReqContext, body api
 
 	result, err := am.TestReceivers(ctx, body)
 	if err != nil {
-		if errors.Is(err, notifier.ErrNoReceivers) {
+		if errors.Is(err, alerting.ErrNoReceivers) {
 			return response.Error(http.StatusBadRequest, "", err)
 		}
 		return response.Error(http.StatusInternalServerError, "", err)
@@ -362,7 +362,7 @@ func statusForTestReceivers(v []notifier.TestReceiverResult) int {
 			if next.Error != nil {
 				var (
 					invalidReceiverErr notifier.InvalidReceiverError
-					receiverTimeoutErr notifier.ReceiverTimeoutError
+					receiverTimeoutErr alerting.ReceiverTimeoutError
 				)
 				if errors.As(next.Error, &invalidReceiverErr) {
 					numBadRequests += 1

pkg/services/ngalert/api/api_alertmanager_test.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/go-openapi/strfmt"
+	"github.com/grafana/alerting/alerting"
 	amv2 "github.com/prometheus/alertmanager/api/v2/models"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/stretchr/testify/require"
@@ -127,7 +128,7 @@ func TestStatusForTestReceivers(t *testing.T) {
 				Name:   "test1",
 				UID:    "uid1",
 				Status: "failed",
-				Error:  notifier.ReceiverTimeoutError{},
+				Error:  alerting.ReceiverTimeoutError{},
 			}},
 		}, {
 			Name: "test2",
@@ -135,7 +136,7 @@ func TestStatusForTestReceivers(t *testing.T) {
 				Name:   "test2",
 				UID:    "uid2",
 				Status: "failed",
-				Error:  notifier.ReceiverTimeoutError{},
+				Error:  alerting.ReceiverTimeoutError{},
 			}},
 		}}))
 	})