Disable caching for retrolite directive

[kolibril13]

Related to https://github.com/jupyterlite/jupyterlite/issues/1067

When I go to the retro-lite example https://jupyterlite-sphinx.readthedocs.io/en/latest/directives/retrolite.html with a specific notebook (.. retrolite:: my_notebook.ipynb), and make some changes, these changes are permanent and there is no way to get back to the original example. Similar how @agoose77 solved that issue, it would be great to have a similar solution for this jupyterlite-sphinx directive. https://github.com/jupyterlite/jupyterlite/issues/1067#issuecomment-1523875403