erp5_web_renderjs_ui_test: wait for page loaded

this commit should fix random plus button not present issue when open sort editor
the reason is sort editor is opened before launcher call editor_panel.close()
so wait for page loaded before open sort editor

bt5/erp5_web_renderjs_ui_test/SkinTemplateItem/portal_skins/erp5_web_renderjs_ui_test/Zuite_CommonTemplateForRenderjsUi.zpt

@@ -68,6 +68,7 @@
     <tal:block metal:use-macro="here/Zuite_CommonTemplateForRenderjsUi/macros/triggle_filter" />
     <tal:block metal:use-macro="here/Zuite_CommonTemplateForRenderjsUi/macros/trash_editor_configuration" />
     <tal:block metal:use-macro="here/Zuite_CommonTemplateForRenderjsUi/macros/submit_filter" />
+    <tal:block metal:use-macro="here/Zuite_CommonTemplateForRenderjsUi/macros/wait_for_content_loaded" />
     <tal:block metal:use-macro="here/Zuite_CommonTemplateForRenderjsUi/macros/wait_for_listbox_loaded" />
   </tal:block>