Alerting: use 'Grafana IRM' wording in alerting contact point (#102014)

* chore: use 'Grafana IRM' wording in alerting contact point

* revert temp condition change

* remove unneeded ts assertion

* more renaming

* use translations

* update test

* running make i18n-extract

* avoid "simple" word in copy

pkg/services/ngalert/notifier/channels_config/available_channels.go

@@ -425,9 +425,9 @@ func GetAvailableNotifiers() []*NotifierPlugin {
 		},
 		{
 			Type:        "oncall",
-			Name:        "Grafana OnCall",
-			Description: "Sends alerts to Grafana OnCall",
-			Heading:     "Grafana OnCall settings",
+			Name:        "Grafana IRM",
+			Description: "Sends alerts to Grafana IRM",
+			Heading:     "Grafana IRM settings",
 			Options: []NotifierOption{
 				{
 					Label:        "URL",