Alerting: Fix "Not Implemented" responses (#57710)

* fix swagger spec, return 404 instead of 501 when an endpoint does not exist

* update number of paths in authorization_test.go

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

@@ -76,39 +76,6 @@
             }
           }
         }
-      },
-      "post": {
-        "description": "create alertmanager alerts",
-        "tags": [
-          "alertmanager"
-        ],
-        "operationId": "RoutePostGrafanaAMAlerts",
-        "parameters": [
-          {
-            "name": "PostableAlerts",
-            "in": "body",
-            "schema": {
-              "type": "array",
-              "items": {
-                "$ref": "#/definitions/postableAlert"
-              }
-            }
-          }
-        ],
-        "responses": {
-          "200": {
-            "description": "Ack",
-            "schema": {
-              "$ref": "#/definitions/Ack"
-            }
-          },
-          "400": {
-            "description": "ValidationError",
-            "schema": {
-              "$ref": "#/definitions/ValidationError"
-            }
-          }
-        }
       }
     },
     "/api/alertmanager/grafana/api/v2/alerts/groups": {
@@ -992,75 +959,6 @@
         }
       }
     },
-    "/api/alertmanager/{DatasourceUID}/config/api/v1/receivers/test": {
-      "post": {
-        "tags": [
-          "alertmanager"
-        ],
-        "summary": "Test Grafana managed receivers without saving them.",
-        "operationId": "RoutePostTestReceivers",
-        "parameters": [
-          {
-            "name": "Body",
-            "in": "body",
-            "schema": {
-              "$ref": "#/definitions/TestReceiversConfigBodyParams"
-            }
-          },
-          {
-            "type": "string",
-            "description": "DatasoureUID should be the datasource UID identifier",
-            "name": "DatasourceUID",
-            "in": "path",
-            "required": true
-          }
-        ],
-        "responses": {
-          "200": {
-            "description": "Ack",
-            "schema": {
-              "$ref": "#/definitions/Ack"
-            }
-          },
-          "207": {
-            "description": "MultiStatus",
-            "schema": {
-              "$ref": "#/definitions/MultiStatus"
-            }
-          },
-          "400": {
-            "description": "ValidationError",
-            "schema": {
-              "$ref": "#/definitions/ValidationError"
-            }
-          },
-          "403": {
-            "description": "PermissionDenied",
-            "schema": {
-              "$ref": "#/definitions/PermissionDenied"
-            }
-          },
-          "404": {
-            "description": "NotFound",
-            "schema": {
-              "$ref": "#/definitions/NotFound"
-            }
-          },
-          "408": {
-            "description": "Failure",
-            "schema": {
-              "$ref": "#/definitions/Failure"
-            }
-          },
-          "409": {
-            "description": "AlertManagerNotReady",
-            "schema": {
-              "$ref": "#/definitions/AlertManagerNotReady"
-            }
-          }
-        }
-      }
-    },
     "/api/prometheus/grafana/api/v1/alerts": {
       "get": {
         "description": "gets the current alerts",
@@ -5842,7 +5740,6 @@
       "$ref": "#/definitions/alertGroup"
     },
     "alertGroups": {
-      "description": "AlertGroups alert groups",
       "type": "array",
       "items": {
         "$ref": "#/definitions/alertGroup"
@@ -6005,6 +5902,7 @@
       "$ref": "#/definitions/gettableAlert"
     },
     "gettableAlerts": {
+      "description": "GettableAlerts gettable alerts",
       "type": "array",
       "items": {
         "$ref": "#/definitions/gettableAlert"
@@ -6214,7 +6112,6 @@
       }
     },
     "postableSilence": {
-      "description": "PostableSilence postable silence",
       "type": "object",
       "required": [
         "comment",