Issue #2866811 by arunkumark, longwave, tar_inet, joelpittet, alexpott: Update...

Issue #2866811 by arunkumark, longwave, tar_inet, joelpittet, alexpott: Update stylelint rule function-linear-gradient-no-nonstandard-direction to be consistent with Drupal's CSS standards

(cherry picked from commit d69b0771)