Unbreak a change..

Author: bergmania

src/Umbraco.Core/Constants-SystemDirectories.cs

@@ -45,10 +45,12 @@ public static class SystemDirectories
 
             public const string AppPlugins = "/App_Plugins";
 
+
             [Obsolete("Use PluginIcons instead")]
-            public const string AppPluginIcons = "/Backoffice/Icons";
+            public static string AppPluginIcons => "/Backoffice/Icons";
+
             public const string PluginIcons = "/backoffice/icons";
-            
+
             public const string CreatedPackages = "/created-packages";