Language dropdown hidden for narrow displays

Originally reported by @svrnm via https://github.com/open-telemetry/opentelemetry.io/issues/4597:

> When I go to opentelemetry.io with a mobile browser the language drop down is not visible
>
> ![image](https://github.com/google/docsy/assets/4140793/9441ea2a-3712-4cce-9404-ecd508f62e32)


