Remove AdsLoader listeners on releasing ImaAdsLoader

Issue: #4114
PiperOrigin-RevId: 227516509

RELEASENOTES.md

@@ -27,6 +27,8 @@
   * Rename TaskState to DownloadState.
 * Add support for SHOUTcast ICY metadata
   ([#3735](https://github.com/google/ExoPlayer/issues/3735)).
+* IMA extension: Clear ads loader listeners on release
+  ([#4114](https://github.com/google/ExoPlayer/issues/4114)).
 
 ### 2.9.3 ###
 

extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java

@@ -598,6 +598,8 @@ public final class ImaAdsLoader
       adsManager.destroy();
       adsManager = null;
     }
+    adsLoader.removeAdsLoadedListener(/* adsLoadedListener= */ this);
+    adsLoader.removeAdErrorListener(/* adErrorListener= */ this);
     imaPausedContent = false;
     imaAdState = IMA_AD_STATE_NONE;
     pendingAdLoadError = null;