Issue #2866801 by harsha012, joelpittet, BrightBold, droplet, Akshay kashyap, arunkumark, bmx269: Update stylelint rules color-hex-length to be consistent with Drupal's CSS standards

Issue #2939940 by bmx269, joelpittet: Update stylelint rules color-hex-case to be consistent with Drupal's CSS standards