Revert "Modified one flyout in the FlyoutDemo"

This reverts commit f5ac9b3479db05b4cc4931492fe3586511de646d.
Revert "Enabled the AnimateOpacity in Flyout.xaml"

This reverts commit a32978c63f26f9abf1f280bb74215c1e6db0669e.
Revert "Added AnimateOpacity to Flyout.cs"

This reverts commit 956ff000d6b7828b6e0b4fbaf16e7936d36edb07.