Version listing needs to show hidden versions if active

[ericholscher]

With the Addons data we're returning, if the current version is active, we likely need to add it to the list of versions somehow.

You can see the issue here, where it's filtered out of the list:

[humitos]

We have to add config.versions.current.hidden to this condition as well: https://github.com/readthedocs/sphinx_rtd_theme/blob/ccf31144c997954aaa9b50839d670b0d282ae824/sphinx_rtd_theme/static/js/versions.js_t#L161-L163