Expose custom field support for create group and create category

assets/javascripts/discourse/components/wizard-custom-action.js.es6

@@ -26,7 +26,7 @@ export default Component.extend(UndoChanges, {
   groupPropertyTypes: selectKitContent(['id', 'name']),
   hasAdvanced: or('hasCustomFields', 'routeTo'),
   showAdvanced: and('hasAdvanced', 'action.type'),
-  hasCustomFields: or('basicTopicFields', 'updateProfile'),
+  hasCustomFields: or('basicTopicFields', 'updateProfile', 'createGroup', 'createCategory'),
   basicTopicFields: or('createTopic', 'sendMessage', 'openComposer'),
   publicTopicFields: or('createTopic', 'openComposer'),
   showSkipRedirect: or('createTopic', 'sendMessage'),

assets/javascripts/discourse/lib/wizard-schema.js.es6

@@ -164,7 +164,8 @@ const action = {
       color: null,
       text_color: "FFFFFF",
       parent_category_id: null,
-      permissions: null
+      permissions: null,
+      custom_fields: null
     },
     create_group: {
       name: null,
@@ -177,7 +178,8 @@ const action = {
       mentionable_level: null,
       messageable_level: null,
       visibility_level: null,
-      members_visibility_level: null
+      members_visibility_level: null,
+      custom_fields: null
     }
   },
   mapped: [