Alerting: Update Swagger spec (#74300)

chore: update alerting swagger spec

Co-authored-by: rwwiv <rwwiv@users.noreply.github.com>

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

@@ -4194,7 +4194,6 @@
    "type": "object"
   },
   "gettableAlert": {
-   "description": "GettableAlert gettable alert",
    "properties": {
     "annotations": {
      "$ref": "#/definitions/labelSet"
@@ -4250,6 +4249,7 @@
    "type": "object"
   },
   "gettableAlerts": {
+   "description": "GettableAlerts gettable alerts",
    "items": {
     "$ref": "#/definitions/gettableAlert"
    },
@@ -4304,6 +4304,7 @@
    "type": "object"
   },
   "gettableSilences": {
+   "description": "GettableSilences gettable silences",
    "items": {
     "$ref": "#/definitions/gettableSilence"
    },
@@ -4492,7 +4493,6 @@
    "type": "object"
   },
   "receiver": {
-   "description": "Receiver receiver",
    "properties": {
     "active": {
      "description": "active",