Alerting: update authorization logic to use proper legacy roles when fine-grained access is disabled (#46931)

* require legacy Editor for post, put, delete endpoints
* require user to be signed in on group level because handler that checks that user has role Editor does not check it is signed in

pkg/services/ngalert/api/tooling/swagger-codegen/templates/controller-api.mustache

@@ -44,6 +44,6 @@ func (api *API) Register{{classname}}Endpoints(srv {{classname}}ForkingService,
 			m,
 		),
   ){{/operation}}{{/operations}}
-	})
+	}, middleware.ReqSignedIn)
 }{{#operation}}
 {{/operation}}{{/operations}}