docs: mkdocs conditional build in RTD

[lwasser]

I have tested this for sphinx and the following does not work:

`- hatch run docs:build -- --strict --site-dir "${READTHEDOCS_OUTPUT}/html"`

it's setup that way for sphinx and i wonder if we have to update it to be a direct command that calls the RTD path rather than a hatch command with an added set of variables. I don't know if that works with hatch as written.

I will adjust the Sphinx size, but we will also need to test the MkDocs side and potentially update the template.