fix swagger spec for receivers API response (#57124)

pkg/services/ngalert/api/tooling/api.json

@@ -3405,7 +3405,6 @@
    "type": "object"
   },
   "gettableAlert": {
-   "description": "GettableAlert gettable alert",
    "properties": {
     "annotations": {
      "$ref": "#/definitions/labelSet"
@@ -3467,7 +3466,6 @@
    "type": "array"
   },
   "gettableSilence": {
-   "description": "GettableSilence gettable silence",
    "properties": {
     "comment": {
      "description": "comment",
@@ -4474,6 +4472,17 @@
  "produces": [
   "application/json"
  ],
+ "responses": {
+  "receiversResponse": {
+   "description": "",
+   "schema": {
+    "items": {
+     "$ref": "#/definitions/receiver"
+    },
+    "type": "array"
+   }
+  }
+ },
  "schemes": [
   "http",
   "https"