fix returning null issue

src/Umbraco.Web.BackOffice/Authorization/UserGroupHandler.cs

@@ -42,11 +42,17 @@ namespace Umbraco.Web.BackOffice.Authorization
 
             var queryString = _httpContextAcessor.HttpContext?.Request.Query;
             if (queryString == null)
-                return null;
+            {
+                // must succeed this requirement since we cannot process it
+                return Task.FromResult(true);
+            }   
 
             var ids = queryString.Where(x => x.Key == requirement.QueryStringName).ToArray();
             if (ids.Length == 0)
-                return null;
+            {
+                // must succeed this requirement since we cannot process it
+                return Task.FromResult(true);
+            }
 
             var intIds = ids.Select(x => x.Value.TryConvertTo<int>()).Where(x => x.Success).Select(x => x.Result).ToArray();
             var authHelper = new UserGroupEditorAuthorizationHelper(