[OSX] any borderstyle can enter fullscreen mode.

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

@@ -668,7 +668,7 @@ private:
                 return E_POINTER;
             }
             
-            if(([Window styleMask] & NSFullScreenWindowMask) == NSFullScreenWindowMask)
+            if(([Window styleMask] & NSWindowStyleMaskFullScreen) == NSWindowStyleMaskFullScreen)
             {
                 *ret = FullScreen;
                 return S_OK;
@@ -701,6 +701,8 @@ private:
         [Window setTitlebarAppearsTransparent:NO];
         [Window setTitle:_lastTitle];
         
+        [Window setStyleMask:NSWindowStyleMaskTitled | NSWindowStyleMaskResizable];
+        
         [Window toggleFullScreen:nullptr];
     }