Add support for the predictive back gesture

The predictive back gesture feature was introduced in Android 13 but will be available on Android 14. We should prepare the app and enable the feature.

On the Android 13 migration, we updated super.onBackPressed() calls with the function below.

fun AppCompatActivity.onBackPressedCompat(onBackPressedCallback: OnBackPressedCallback) {
    onBackPressedCallback.isEnabled = false
    onBackPressedDispatcher.onBackPressed()
    onBackPressedCallback.isEnabled = true
}

This function mimics the super.onBackPressed behavior but breaks the predictive back gesture behavior, as explained here. Therefore, before enabling predictive back gesture, all usages of onBackPressedCompat should be reviewed and updated.

• Here is a StackOverflow comment on how we can update our back pressed approach to the new ahead-of-time approach.
• Further discussion initiating this issue is on https://github.com/wordpress-mobile/WordPress-Android/pull/18019.
• Official document: https://developer.android.com/guide/navigation/predictive-back-gesture

Start by searching for all usages of onBackPressedCompat and read the linked Android predictive back documentation and discussion. Review each usage against the ahead-of-time back approach, then enable predictive back once the affected usages have been updated and the gesture behavior works correctly.