This example doesn't actually manage its own app bar; it only presents one. This fixes a bug where the example did not show a navigation bar at all.
PiperOrigin-RevId: 310870101
This new flag allows view controllers to control the visibility of their app bar via the standard UINavigationController setNavigationBarHidden: APIs. When enabled, calls to these APIs will result in the AppBar's visibility being adjusted.
Closes https://github.com/material-components/material-components-ios/issues/5185