Remove the first @todo note in the css/theme/media-library.css file

Problem/Motivation

The css/theme/media-library.css file contains the following lines.

/**
 * @todo Reuse or build on vertical tabs styling for the media library menu.
 *   https://www.drupal.org/project/drupal/issues/3023767
 */

#3023767: Reuse or build on vertical tabs styling in media library has been closed as won't fix for the following reason.

Although we did have to copy the styles for Media Library, we can't really reuse the ones from vertical tabs, or refactor them to be compatible. The vertical tab styles in core where not really meant to work with any ol' list of links, and it'd be a lot of effort, for very little reward, to change that.

Proposed resolution

Remove the full comment.