fix(audio-tracks): missing AD icon in Safari (#9153)

Author: amtins

src/css/components/_audio.scss

@@ -10,6 +10,7 @@
 }
 
 // Mark a main-desc-menu-item (main + description) or description item with a trailing Audio Description icon
+.video-js .vjs-audio-button + .vjs-menu .vjs-description-menu-item .vjs-menu-item-text .vjs-icon-placeholder:before,
 .video-js .vjs-audio-button + .vjs-menu .vjs-descriptions-menu-item .vjs-menu-item-text .vjs-icon-placeholder:before,
 .video-js .vjs-audio-button + .vjs-menu .vjs-main-desc-menu-item .vjs-menu-item-text .vjs-icon-placeholder:before {
   font-family: VideoJS;

src/js/control-bar/audio-track-controls/audio-track-menu-item.js

@@ -51,7 +51,7 @@ class AudioTrackMenuItem extends MenuItem {
     const el = super.createEl(type, props, attrs);
     const parentSpan = el.querySelector('.vjs-menu-item-text');
 
-    if (['main-desc', 'descriptions'].indexOf(this.options_.track.kind) >= 0) {
+    if (['main-desc', 'descriptions', 'description'].indexOf(this.options_.track.kind) >= 0) {
       parentSpan.appendChild(Dom.createEl('span', {
         className: 'vjs-icon-placeholder'
       }, {