Alerting: Drop NamespaceID from responses on unstable ngalert API endpoints in favor of NamespaceUID (#79359)

* Drop from API response

* Drop from swagger docs

* Drop from integration tests

* regenerate public swagger docs

* Drop from frontend

* Drop asserts for namespaceID field

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

@@ -1431,10 +1431,6 @@
     "is_paused": {
      "type": "boolean"
     },
-    "namespace_id": {
-     "format": "int64",
-     "type": "integer"
-    },
     "namespace_uid": {
      "type": "string"
     },
@@ -4472,7 +4468,6 @@
    "type": "array"
   },
   "integration": {
-   "description": "Integration integration",
    "properties": {
     "lastNotifyAttempt": {
      "description": "A timestamp indicating the last attempt to deliver a notification regardless of the outcome.\nFormat: date-time",