refactor: simplify music metadata processing by removing unused code and improving album signal detection

app/ytdl.py

@@ -23,7 +23,7 @@ from yt_dlp.postprocessor.common import PostProcessor
 from yt_dlp.utils import STR_FORMAT_RE_TMPL, STR_FORMAT_TYPES
 import bg_tasks
 from dl_formats import get_format, get_opts, AUDIO_FORMATS, merge_ytdl_option_layers
-from music_metadata import MusicMetadataPreProcessor, MusicMetadataWriterPostProcessor
+from music_metadata import MusicMetadataPreProcessor
 from datetime import datetime
 from state_store import AtomicJsonStore, from_json_compatible, read_legacy_shelf, to_json_compatible
 from subscriptions import _entry_id
@@ -601,12 +601,10 @@ class Download:
             ydl.add_post_processor(
                 MusicMetadataPreProcessor(
                     ydl,
-                    source_url=getattr(self.info, 'url', None),
                     source_entry=getattr(self.info, 'entry', None),
                 ),
                 when='pre_process',
             )
-            ydl.add_post_processor(MusicMetadataWriterPostProcessor(ydl), when='after_move')
         return ydl
 
     def _download(self):