fix: Fix pointer events timestamp being in ms instead of ticks on X11

src/Uno.UI.Runtime.Skia.X11/X11PointerInputSource.cs

@@ -188,7 +188,7 @@ private PointerPoint CreatePointFromCurrentState(IntPtr time)
 		// This matches the format of WinUI. See also: https://github.com/unoplatform/uno/issues/14535
 		var point = new PointerPoint(
 			frameId: (uint)time, // UNO TODO: How should set the frame, timestamp may overflow.
-			timestamp: (uint)time,
+			timestamp: (ulong)(time * TimeSpan.TicksPerMillisecond),
 			PointerDevice.For(PointerDeviceType.Mouse),
 			0, // TODO: XInput
 			new Point(_mousePosition.X / scale, _mousePosition.Y / scale),