Solve CodeQL issue

MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs

@@ -904,7 +904,8 @@ namespace MediaBrowser.MediaEncoding.Subtitles
 
         public async Task<string> GetSubtitleFilePath(MediaStream subtitleStream, MediaSourceInfo mediaSource, CancellationToken cancellationToken)
         {
-            var info = await GetReadableFile(mediaSource, subtitleStream, cancellationToken);
+            var info = await GetReadableFile(mediaSource, subtitleStream, cancellationToken)
+                .ConfigureAwait(false);
             return info.Path;
         }