fix(Ads): Fix duplicate Ads when playing interstitials through native HLS player (#7527)

lib/ads/interstitial_ad_manager.js

@@ -367,7 +367,7 @@ shaka.ads.InterstitialAdManager = class {
     }
     let cuepointsChanged = false;
     for (const interstitial of interstitials) {
-      const interstitialId = JSON.stringify(interstitial);
+      const interstitialId = interstitial.id || JSON.stringify(interstitial);
       if (this.interstitialIds_.has(interstitialId)) {
         continue;
       }
@@ -777,6 +777,16 @@ shaka.ads.InterstitialAdManager = class {
     if (hlsInterstitialId) {
       id = /** @type {string} */(hlsInterstitialId.data);
     }
+    const startTime = id == null ?
+        Math.floor(hlsInterstitial.startTime * 10) / 10:
+        hlsInterstitial.startTime;
+    let endTime = hlsInterstitial.endTime;
+    if (hlsInterstitial.endTime && hlsInterstitial.endTime != Infinity &&
+        typeof(hlsInterstitial.endTime) == 'number') {
+      endTime = id == null ?
+          Math.floor(hlsInterstitial.endTime * 10) / 10:
+          hlsInterstitial.endTime;
+    }
     const restrict = hlsInterstitial.values.find((v) => v.key == 'X-RESTRICT');
     let isSkippable = true;
     let canJump = true;
@@ -851,8 +861,8 @@ shaka.ads.InterstitialAdManager = class {
       }
       interstitialsAd.push({
         id,
-        startTime: hlsInterstitial.startTime,
-        endTime: hlsInterstitial.endTime,
+        startTime,
+        endTime,
         uri,
         isSkippable,
         skipOffset,
@@ -901,8 +911,8 @@ shaka.ads.InterstitialAdManager = class {
           if (asset['URI']) {
             interstitialsAd.push({
               id,
-              startTime: hlsInterstitial.startTime,
-              endTime: hlsInterstitial.endTime,
+              startTime,
+              endTime,
               uri: asset['URI'],
               isSkippable,
               skipOffset,