private void updateHandler() {
        handler = new SuperModelController(
                superModelManager.getSuperModelConfigProvider(),
                configDefinitionRepo,
                superModelManager.getGeneration(),
                responseFactory);
    }
Signals that config has been activated for an {@link com.yahoo.vespa.config.server.application.Application}
belonging to a tenant.

@param applicationVersions The activated set of {@link com.yahoo.vespa.config.server.application.Application}s.
configserver/src/main/java/com/yahoo/vespa/config/server/SuperModelRequestHandler.java