Immediately returning from AdminActionAttribute.OnAuthorization upon determining result.

Author: agr

src/NuGetGallery/Filters/AdminActionAttribute.cs

@@ -17,6 +17,7 @@ public override void OnAuthorization(AuthorizationContext filterContext)
             if (!AdminHelper.IsAdminPanelEnabled)
             {
                 filterContext.Result = new HttpStatusCodeResult(HttpStatusCode.Forbidden);
+                return;
             }
 
             Roles = "Admins";