Alerting: Add feature toggle to use the old simplified routing hash generation (#111900)

* Revert "Alerting: Generate simplified routing routes with old fingerprint function (#111893)"

This reverts commit 0da9d49896.

* Add alertingUseNewSimplifiedRoutingHashAlgorithm flag

* Alerting: Add feature toggle to use the old simplified routing hash generation

pkg/services/ngalert/api/api_alertmanager_test.go

@@ -291,7 +291,8 @@ func TestAlertmanagerAutogenConfig(t *testing.T) {
 			1: {AlertmanagerConfiguration: validConfig, OrgID: 1},
 			2: {AlertmanagerConfiguration: validConfigWithoutAutogen, OrgID: 2},
 		}
-		sut.mam = createMultiOrgAlertmanager(t, configs)
+		ft := featuremgmt.WithFeatures(featuremgmt.FlagAlertingUseNewSimplifiedRoutingHashAlgorithm)
+		sut.mam = createMultiOrgAlertmanager(t, configs, withAMFeatureToggles(ft))
 		return sut, configs
 	}
 
@@ -577,9 +578,29 @@ func createSut(t *testing.T) AlertmanagerSrv {
 	}
 }
 
-func createMultiOrgAlertmanager(t *testing.T, configs map[int64]*ngmodels.AlertConfiguration) *notifier.MultiOrgAlertmanager {
+type createMultiOrgAMOptions struct {
+	featureToggles featuremgmt.FeatureToggles
+}
+
+type createMultiOrgAMOptionsFunc func(*createMultiOrgAMOptions)
+
+func withAMFeatureToggles(toggles featuremgmt.FeatureToggles) createMultiOrgAMOptionsFunc {
+	return func(opts *createMultiOrgAMOptions) {
+		opts.featureToggles = toggles
+	}
+}
+
+func createMultiOrgAlertmanager(t *testing.T, configs map[int64]*ngmodels.AlertConfiguration, opts ...createMultiOrgAMOptionsFunc) *notifier.MultiOrgAlertmanager {
 	t.Helper()
 
+	options := createMultiOrgAMOptions{
+		featureToggles: featuremgmt.WithFeatures(),
+	}
+
+	for _, opt := range opts {
+		opt(&options)
+	}
+
 	configStore := notifier.NewFakeConfigStore(t, configs)
 	orgStore := notifier.NewFakeOrgStore(t, []int64{1, 2, 3})
 	provStore := ngfakes.NewFakeProvisioningStore()
@@ -610,7 +631,7 @@ func createMultiOrgAlertmanager(t *testing.T, configs map[int64]*ngmodels.AlertC
 		ngfakes.NewFakeReceiverPermissionsService(),
 		log.New("testlogger"),
 		secretsService,
-		featuremgmt.WithManager(),
+		options.featureToggles,
 		nil,
 	)
 	require.NoError(t, err)