With Android Auto wouldn't you use the cars display anyway?
Not used any apps with this issue but you can set certain ones to hide the camera within the Display Options.
Edit....
Actually the option only sets Auto or Full Screen per individual app, would have made more sense having Hide Camera in there.
No my car doesn't have android auto, I use it as an interface that is easier to use when driving with it in a holder on the dash.
Yeah I saw that setting where you can only "hide the camera" all of the time, not per app.