Version and language selectors are barely visible in the light theme.

### Describe the bug

Version and language selectors are barely visible in the light theme. Since we already use the Read the Docs [flyout menu add-on](
https://docs.readthedocs.com/platform/stable/flyout-menu.html) (see bottom-right corner of the page), which contains the same information, we could consider removing them from the sidebar. Or fix the layout and disable the flyout menu.

### To reproduce

Switch the color theme to the light version (see screenshots below). The version and language selectors are barely visible in the light theme.

### Expected behavior

Version and language selectors should be visible in the light theme, as they are in the dark one.