Fix EPI.seekTo to balance operation acks when seeking during an ad

This regression was introduced in
https://github.com/google/ExoPlayer/commit/b1e9257de143e9f377895b63868ef47b4fc0eea9

Issue: #8349

PiperOrigin-RevId: 347802049

RELEASENOTES.md

@@ -2,6 +2,9 @@
 
 ### 2.12.3 (???-??-??) ###
 
+*   Core library:
+    *   Fix playback issues after seeking during an ad
+        ([#8349](https://github.com/google/ExoPlayer/issues/8349)).
 *   UI:
     *   Fix issue where pop-up menus belonging to `StyledPlayerControlView`
         would not be dismissed when tapping outside of the menu area or pressing

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java

@@ -601,8 +601,10 @@ import java.util.concurrent.TimeoutException;
       // general because the midroll ad preceding the seek destination must be played before the
       // content position can be played, if a different ad is playing at the moment.
       Log.w(TAG, "seekTo ignored because an ad is playing");
-      playbackInfoUpdateListener.onPlaybackInfoUpdate(
-          new ExoPlayerImplInternal.PlaybackInfoUpdate(playbackInfo));
+      ExoPlayerImplInternal.PlaybackInfoUpdate playbackInfoUpdate =
+          new ExoPlayerImplInternal.PlaybackInfoUpdate(this.playbackInfo);
+      playbackInfoUpdate.incrementPendingOperationAcks(1);
+      playbackInfoUpdateListener.onPlaybackInfoUpdate(playbackInfoUpdate);
       return;
     }
     @Player.State