Alerting: Update RuleGroupConfig definitions with missing fields (#115850)

* Alerting: Update RuleGroupConfig definitions with missing fields

This update adds previously missing fields to the `RuleGroupConfig` structs to
ensure compatibility with external Prometheus-like rulers.

Includes:
- `labels`: per https://github.com/prometheus/prometheus/pull/11474
- `remote_write`: per https://github
.com/grafana/mimir/blob/56f33fed6254fee5a53bde1eab36c604863e3d5f/pkg/mimirtool/rules/rwrulefmt/rulefmt.go#L16

Note: This does not add full support in Grafana; it only allows these fields to
pass through the alerting proxy without causing unmarshal errors when using
external rulers.

* Update OpenAPI spec

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

@@ -5072,12 +5072,6 @@
     "BacktestConfig": {
       "type": "object",
       "properties": {
-        "annotations": {
-          "type": "object",
-          "additionalProperties": {
-            "type": "string"
-          }
-        },
         "condition": {
           "type": "string"
         },
@@ -5087,8 +5081,16 @@
             "$ref": "#/definitions/AlertQuery"
           }
         },
+        "exec_err_state": {
+          "type": "string",
+          "enum": [
+            "OK",
+            "Alerting",
+            "Error"
+          ]
+        },
         "for": {
-          "$ref": "#/definitions/Duration"
+          "type": "string"
         },
         "from": {
           "type": "string",
@@ -5097,12 +5099,22 @@
         "interval": {
           "$ref": "#/definitions/Duration"
         },
+        "keep_firing_for": {
+          "type": "string"
+        },
         "labels": {
           "type": "object",
           "additionalProperties": {
             "type": "string"
           }
         },
+        "missing_series_evals_to_resolve": {
+          "type": "integer",
+          "format": "int64"
+        },
+        "namespace_uid": {
+          "type": "string"
+        },
         "no_data_state": {
           "type": "string",
           "enum": [
@@ -5111,12 +5123,18 @@
             "OK"
           ]
         },
+        "rule_group": {
+          "type": "string"
+        },
         "title": {
           "type": "string"
         },
         "to": {
           "type": "string",
           "format": "date-time"
+        },
+        "uid": {
+          "type": "string"
         }
       }
     },
@@ -6239,6 +6257,12 @@
         "interval": {
           "$ref": "#/definitions/Duration"
         },
+        "labels": {
+          "type": "object",
+          "additionalProperties": {
+            "type": "string"
+          }
+        },
         "limit": {
           "type": "integer",
           "format": "int64"
@@ -6249,6 +6273,12 @@
         "query_offset": {
           "type": "string"
         },
+        "remote_write": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/RemoteWriteConfig"
+          }
+        },
         "rules": {
           "type": "array",
           "items": {
@@ -7569,6 +7599,12 @@
         "interval": {
           "$ref": "#/definitions/Duration"
         },
+        "labels": {
+          "type": "object",
+          "additionalProperties": {
+            "type": "string"
+          }
+        },
         "limit": {
           "type": "integer",
           "format": "int64"
@@ -7579,6 +7615,12 @@
         "query_offset": {
           "type": "string"
         },
+        "remote_write": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/RemoteWriteConfig"
+          }
+        },
         "rules": {
           "type": "array",
           "items": {
@@ -8243,6 +8285,14 @@
         }
       }
     },
+    "RemoteWriteConfig": {
+      "type": "object",
+      "properties": {
+        "url": {
+          "type": "string"
+        }
+      }
+    },
     "ResponseDetails": {
       "type": "object",
       "properties": {
@@ -8520,6 +8570,12 @@
         "interval": {
           "$ref": "#/definitions/Duration"
         },
+        "labels": {
+          "type": "object",
+          "additionalProperties": {
+            "type": "string"
+          }
+        },
         "limit": {
           "type": "integer",
           "format": "int64"
@@ -8530,6 +8586,12 @@
         "query_offset": {
           "type": "string"
         },
+        "remote_write": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/RemoteWriteConfig"
+          }
+        },
         "rules": {
           "type": "array",
           "items": {