fix(volume-panel): a long press on the volume button displays the vol…

…ume slider on touch devices

Prevents the `volume slider` from displaying when a long press is made on the `volume button`,
forcing the user to make a long press or tap elsewhere on the player or page to make the `volume slider` disappear.

- adds class `.vjs-touch-enabled` to pseudo-class `:not` at the root of the rule displaying the `volume slider`

src/css/components/_volume.scss

@@ -34,7 +34,7 @@
   margin-left: -1px;
 }
 
-.video-js .vjs-volume-panel {
+.video-js:not(.vjs-touch-enabled) .vjs-volume-panel {
   &.vjs-hover .vjs-volume-control,
   &:active .vjs-volume-control,
   &:focus  .vjs-volume-control,