fix(Ads): Limit interstitial duration to actual duration if available (#7480)

Currently, if the interstitial lasts 30 and we have a stream that lasts
31 seconds, we would go back to live after the interstitial, but with 1
extra second of latency. This PR solves this by limiting the play range
to 30.

Author: avelad

lib/ads/interstitial_ad_manager.js

@@ -536,11 +536,26 @@ shaka.ads.InterstitialAdManager = class {
     });
     try {
       this.updatePlayerConfig_();
+      // playRangeEnd in src= causes the ended event not to be fired when that
+      // position is reached. So we don't use it because we would never go back
+      // to the main stream.
+      const loadMode = this.basePlayer_.getLoadMode();
+      if (loadMode == shaka.Player.LoadMode.MEDIA_SOURCE &&
+          interstitial.startTime && interstitial.endTime &&
+          interstitial.endTime != Infinity &&
+          interstitial.startTime != interstitial.endTime) {
+        const duration = interstitial.endTime - interstitial.startTime;
+        if (duration > 0) {
+          this.player_.configure('playRangeEnd', duration);
+        }
+      }
       if (interstitial.playoutLimit) {
         playoutLimitTimer = new shaka.util.Timer(() => {
           ad.skip();
         }).tickAfter(interstitial.playoutLimit);
-        this.player_.configure('playRangeEnd', interstitial.playoutLimit);
+        if (loadMode == shaka.Player.LoadMode.MEDIA_SOURCE) {
+          this.player_.configure('playRangeEnd', interstitial.playoutLimit);
+        }
       }
       await this.player_.attach(this.video_);
       if (this.preloadManagerInterstitials_.has(interstitial)) {