fix: correct parsing of audio release date property

Read full date from ffmpeg probe.

MediaBrowser.Providers/MediaInfo/AudioFileProber.cs

@@ -228,6 +228,7 @@ namespace MediaBrowser.Providers.MediaInfo
 
             audio.RunTimeTicks = mediaInfo.RunTimeTicks;
             audio.Size = mediaInfo.Size;
+            audio.PremiereDate = mediaInfo.PremiereDate;
 
             if (!audio.IsLocked)
             {
@@ -370,7 +371,6 @@ namespace MediaBrowser.Providers.MediaInfo
                 {
                     var year = Convert.ToInt32(tags.Year);
                     audio.ProductionYear = year;
-                    audio.PremiereDate = new DateTime(year, 01, 01);
                 }
 
                 if (!audio.LockedFields.Contains(MetadataField.Genres))