fix(big-play-button): component remains displayed when seeking (#8484)

This issue happen when the `player` has the class `vjs-show-big-play-button-on-pause` and a `seek` occurs,
resulting in the `loadingSpinner` being hidden behind the `bigPlayButton`.

- Avoids displaying `bigPlayButton` while `seeking`

src/css/components/_big-play.scss

@@ -57,6 +57,6 @@
 }
 
 // Show big play button if video is paused and .vjs-show-big-play-button-on-pause is set on video element
-.vjs-has-started.vjs-paused.vjs-show-big-play-button-on-pause .vjs-big-play-button {
+.vjs-has-started.vjs-paused.vjs-show-big-play-button-on-pause:not(.vjs-seeking, .vjs-scrubbing) .vjs-big-play-button {
   display: block;
 }