[v9.2.x] Alerting: Use correct response body for silence post API (#57126)

Co-authored-by: Yuriy Tseretyan <yuriy.tseretyan@grafana.com>

pkg/services/ngalert/api/tooling/definitions/alertmanager.go

@@ -199,7 +199,7 @@ import (
 // create silence
 //
 //     Responses:
-//       201: gettableSilence
+//       201: postSilencesOKBody
 //       400: ValidationError
 
 // swagger:route POST /api/alertmanager/{DatasourceUID}/api/v2/silences alertmanager RouteCreateSilence
@@ -207,7 +207,7 @@ import (
 // create silence
 //
 //     Responses:
-//       201: gettableSilence
+//       201: postSilencesOKBody
 //       400: ValidationError
 //       404: NotFound
 
@@ -389,6 +389,12 @@ func NewGettableStatus(cfg *PostableApiAlertingConfig) *GettableStatus {
 // swagger:model postableSilence
 type PostableSilence = amv2.PostableSilence
 
+// swagger:model postSilencesOKBody
+type PostSilencesOKBody struct { // vendored from "github.com/prometheus/alertmanager/api/v2/restapi/operations/silence/PostSilencesOKBody" because import brings too many other things
+	// silence ID
+	SilenceID string `json:"silenceID,omitempty"`
+}
+
 // swagger:model gettableSilences
 type GettableSilences = amv2.GettableSilences