fix obsolescence warnings

Author: janusw

Maui.Tabs/Platforms/iOS/TintableImageEffect.cs

@@ -88,7 +88,7 @@ private void UpdateColor()
         private async Task DelayedPost(int milliseconds, Action action)
         {
             await Task.Delay(milliseconds);
-            Device.BeginInvokeOnMainThread(action);
+            MainThread.BeginInvokeOnMainThread(action);
         }
     }
 }

Maui.Tabs/Platforms/iOS/TouchEffectPlatform.cs

@@ -1,6 +1,6 @@
 using System.ComponentModel;
-using Microsoft.Maui.Controls.Compatibility.Platform.iOS;
 using Microsoft.Maui.Controls.Platform;
+using Microsoft.Maui.Platform;
 using ObjCRuntime;
 using Sharpnado.Tabs.Effects.iOS.GestureCollectors;
 using Sharpnado.Tabs.Effects.iOS.GestureRecognizers;
@@ -80,7 +80,7 @@ void UpdateEffectColor() {
 
             InternalLogger.Debug($"UpdateEffectColor");
             _alpha = color.Alpha < 1.0 ? 1 : (float)0.3;
-            _layer.BackgroundColor = color.ToUIColor();
+            _layer.BackgroundColor = color.ToPlatform();
         }
 
         void BringLayer() {