chore: remove comment

Author: mxschll

src/tabs/tab-header-bar.scss

@@ -115,11 +115,6 @@ $label-horizontal-spacing: awsui.$space-xs;
   display: flex;
   align-items: stretch;
 
-  &,
-  & > button {
-    // background-color: transparent; // Why was this needed?
-  }
-
   & > .tabs-tab-dismiss,
   & > .tabs-tab-action {
     position: relative;