Revert remains of 'upgrade upsell to course info banner'.

TNL-6381 added an upgrade upsell to course info. In PR #15265, this was
partially removed/moved, but some clean-up work remained.

LEARNER-2026

common/static/sass/edx-pattern-library-shims/base/_variables.scss

@@ -203,6 +203,7 @@ $btn-border-radius:                         $component-border-radius !default;
 $btn-large-padding-vertical: spacing-vertical(small);
 $btn-large-padding-horizontal: spacing-horizontal(mid-large);
 
+
 $btn-base-padding-vertical: spacing-vertical(x-small);
 $btn-base-padding-horizontal: spacing-horizontal(base);
 $btn-base-font-size: font-size(base);