Include AdditionalData when mapping IEntitySlim to EntityBasic

src/Umbraco.Web/Models/Mapping/EntityMapDefinition.cs

@@ -45,6 +45,13 @@ namespace Umbraco.Web.Models.Mapping
             if (source.NodeObjectType == Constants.ObjectTypes.Member && target.Icon.IsNullOrWhiteSpace())
                 target.Icon = "icon-user";
 
+            // NOTE: we're mapping the objects in AdditionalData by object reference here.
+            // it works fine for now, but it's something to keep in mind in the future
+            foreach(var kvp in source.AdditionalData)
+            {
+                target.AdditionalData[kvp.Key] = kvp.Value;
+            }
+
             target.AdditionalData.Add("IsContainer", source.IsContainer);
         }