fix(animation): Fix transition animation not cancelled

BREAKING CHANGE: `VisualState.Setters` are now applied after `VisualTransition.Storyboard`

src/Uno.UI/FeatureConfiguration.cs

@@ -493,6 +493,16 @@ public static class UIElement
 #endif
 		}
 
+		public static class VisualState
+		{
+			/// <summary>
+			/// When this is set, the <see cref="Windows.UI.Xaml.VisualState.Setters"/> will be applied synchronously when changing state,
+			/// unlike UWP which waits the for the end of the <see cref="VisualTransition.Storyboard"/> (if any) to apply them.
+			/// </summary>
+			/// <remarks>This flag is for backward compatibility with old versions of uno and should not be turned on.</remarks>
+			public static bool ApplySettersBeforeTransition { get; set; } = false;
+		}
+
 		public static class WebView
 		{
 #if __ANDROID__

src/Uno.UI/UI/Xaml/Media/Animation/Storyboard.cs

@@ -287,6 +287,7 @@ internal void TurnOverAnimationsTo(Storyboard storyboard)
 					((ITimeline)child).Stop();
 				}
 			}
+
 			State = TimelineState.Stopped;
 		}
 

src/Uno.UI/UI/Xaml/Media/Animation/Timeline.cs

@@ -24,7 +24,7 @@ public Timeline()
 			State = TimelineState.Stopped;
 		}
 
-		protected enum TimelineState
+		protected internal enum TimelineState
 		{
 			Active,
 			Filling,
@@ -46,7 +46,7 @@ protected string[] GetTraceProperties()
 		/// An internally-used property which is essentially equivalent to <see cref="Storyboard.GetCurrentState"/>, except that it 
 		/// distinguishes <see cref="TimelineState.Active"/> from <see cref="TimelineState.Paused"/>.
 		/// </summary>
-		protected TimelineState State { get; set; }
+		protected internal TimelineState State { get; set; }
 
 		public TimeSpan? BeginTime
 		{