Make GraphQL lookahead work for list types

app/graphql/resolvers/concerns/looks_ahead.rb

@@ -67,6 +67,7 @@ def preloads_from_node_selection(selected_fields, fields)
 
   def node_selection(selection = lookahead)
     return selection unless selection&.selected?
+    return selection if selection.field.type.list?
     return selection.selection(:edges).selection(:node) if selection.selects?(:edges)
 
     # Will return a NullSelection object if :nodes is not a selection. This

ee/spec/requests/api/graphql/namespace/work_item_types_spec.rb

@@ -90,7 +90,7 @@
             ... on WorkItemWidgetDefinitionCustomFields {
               customFields {
                 id
-                createdBy { name }
+                selectOptions { value }
               }
             }
           }

spec/support/helpers/graphql_helpers.rb

@@ -893,6 +893,7 @@ def positive_lookahead
       allow(selection).to receive(:selection).and_return(selection)
       allow(selection).to receive(:selections).and_return(selection)
       allow(selection).to receive(:map).and_return(double(include?: true))
+      allow(selection).to receive_message_chain(:field, :type, :list?).and_return(false)
     end
   end