Fix usage of updated Screen properties

This fixes the macOS build

native/Avalonia.Native/src/OSX/Screens.mm

@@ -41,9 +41,9 @@ public:
             ret->WorkingArea.X = [screen visibleFrame].origin.x;
             ret->WorkingArea.Y = ConvertPointY(ToAvnPoint([screen visibleFrame].origin)).Y - ret->WorkingArea.Height;
             
-            ret->PixelDensity = [screen backingScaleFactor];
+            ret->Scaling = [screen backingScaleFactor];
             
-            ret->Primary = index == 0;
+            ret->IsPrimary = index == 0;
             
             return S_OK;
         }

src/Windows/Avalonia.Win32/WinScreen.cs

@@ -7,7 +7,8 @@ namespace Avalonia.Win32
     {
         private readonly IntPtr _hMonitor;
 
-        public WinScreen(double pixelDensity, PixelRect bounds, PixelRect workingArea, bool primary, IntPtr hMonitor) : base(pixelDensity, bounds, workingArea, primary)
+        public WinScreen(double scaling, PixelRect bounds, PixelRect workingArea, bool isPrimary, IntPtr hMonitor)
+            : base(scaling, bounds, workingArea, isPrimary)
         {
             _hMonitor = hMonitor;
         }