[pp/EmbedThumbnail] Fix ffmpeg args for embedding in mp3 (#13720)

Authored by: atsushi2965

yt_dlp/postprocessor/embedthumbnail.py

@@ -90,7 +90,7 @@ class EmbedThumbnailPP(FFmpegPostProcessor):
         if info['ext'] == 'mp3':
             options = [
                 '-c', 'copy', '-map', '0:0', '-map', '1:0', '-write_id3v1', '1', '-id3v2_version', '3',
-                '-metadata:s:v', 'title="Album cover"', '-metadata:s:v', 'comment=Cover (front)']
+                '-metadata:s:v', 'title=Album cover', '-metadata:s:v', 'comment=Cover (front)']
 
             self._report_run('ffmpeg', filename)
             self.run_ffmpeg_multiple_files([filename, thumbnail_filename], temp_filename, options)