NuPlayer does not send MEDIA_PLAYBACK_COMPLETE message in some cases.

When the video's EOS notification arrives at NuPlayer before the audio error notification,
NuPlayer may skip sending the MEDIA_PLAYBACK_COMPLETE notification because the audio decoder still exists.

How to reproduce:
1. Set the seek mode to SEEK_NEXT_SYNC.
2. Play an MP4 video file with an audio track with an error at the beginning.
3. Start play
4. Pause and seek to near the end of the file (beyond the last key position).
5. Resume.
6. The play will not end.

Bug: 264303934

Change-Id: Idc9d6eac69dd411998b049f647874e3c0d1e81d8