This new shift behavior mode enables the flexible header to mimic the behavior of UINavigationController's setNavigationBarHidden:. When the shift behavior is set to this new value, the flexible header can be hidden or shown using the shiftHeaderOnScreenAnimated: and shiftHeaderOffScreenAnimated: APIs, but user interactions will not affect the header's visibility.
Added an example to the configurator to demonstrate the behavior.
Part of https://github.com/material-components/material-components-ios/issues/5185