Moved all PInvokes to a lower class without any relianceon WPF, NotificationIconHelper, TaskbarHelper, SystemPersonalisationHelper are WPF window no more

src/NotificationFlyout.Shared.UI/WndProc/WndProcHandlerReference.cs

@@ -0,0 +1,26 @@
+using System;
+
+namespace NotificationFlyout.Shared.UI.Helpers
+{
+    internal class WndProcHandlerReference
+    {
+        private readonly WeakReference _reference;
+
+        public WndProcHandlerReference(object handler) => _reference = new WeakReference(handler);
+
+        public bool IsDead => _reference.Target == null;
+
+        public void Handle(uint message, IntPtr wParam, IntPtr lParam)
+        {
+            if (_reference.Target == null) return;
+
+            var target = _reference.Target;
+            if (target is IWndProcHandler handler)
+            {
+                handler.Handle(message, wParam, lParam);
+            }
+        }
+
+        public bool Matches(object instance) => _reference.Target == instance;
+    }
+}