Fix MeasurementNotificationService binding (#14439)

Ensure that the MeasurementNotificationService identifer is bound in
singleton scope.
Otherwise it can only be injected once

packages/metrics/src/browser/metrics-frontend-module.ts

@@ -24,5 +24,5 @@ export default new ContainerModule(bind => {
     bind(MeasurementNotificationService).toDynamicValue(ctx => {
         const connection = ctx.container.get(WebSocketConnectionProvider);
         return connection.createProxy<MeasurementNotificationService>(measurementNotificationServicePath);
-    });
+    }).inSingletonScope();
 });