This change makes it possible for header customization options to use appearence API introduces in iOS 13. Thanks to this the default header setting will respect header translucency. Thanks to the appearence API we no longer need to set so many properties in setAnimatedConfig.
- `@available` should not be used with other conditions (not sure if it breaks anything but it does trigger warnings in xcode)
- missing runtime check before using `modalInPresentation`, kept the precompiler instruction so it still builds on older xcodes.
This change fixes the problem when header would update to the previous screen configuration as a result of starting swipe back gesture but never restore to the original one in case swipe back gets cancelled (e.g. user didn't swipe far enough). The problem was that as a result of swipe back we'd apply header config changes but after cancel there was no trigger to reset header to the previous state.
