How do I redisplay a backgrounded HA dashboard on a Google Hub?

I have some nice HA dashboards which I cast to Google Nest hubs using the show_lovelace_view service. It works well but occasionally the dashboard will get ‘backgrounded’ by the hub’s software. It is still playing and I can redisplay it manually from the hub’s menu (Media menu and select the HA Lovelace instance).
I would like to send a text command to the hub via the Google Assistant SDK to redisplay the hidden view programmatically.

Does anyone know the magic Google spell to do this?