[ie/patreon] Extract attachment filename as `alt_title` (#12000)

Authored by: msm595

yt_dlp/extractor/patreon.py

@@ -63,6 +63,7 @@ class PatreonIE(PatreonBaseIE):
         'info_dict': {
             'id': '743933',
             'ext': 'mp3',
+            'alt_title': 'cd166.mp3',
             'title': 'Episode 166: David Smalley of Dogma Debate',
             'description': 'md5:34d207dd29aa90e24f1b3f58841b81c7',
             'uploader': 'Cognitive Dissonance Podcast',
@@ -280,7 +281,7 @@ class PatreonIE(PatreonBaseIE):
         video_id = self._match_id(url)
         post = self._call_api(
             f'posts/{video_id}', video_id, query={
-                'fields[media]': 'download_url,mimetype,size_bytes',
+                'fields[media]': 'download_url,mimetype,size_bytes,file_name',
                 'fields[post]': 'comment_count,content,embed,image,like_count,post_file,published_at,title,current_user_can_view',
                 'fields[user]': 'full_name,url',
                 'fields[post_tag]': 'value',
@@ -317,6 +318,7 @@ class PatreonIE(PatreonBaseIE):
                         'ext': ext,
                         'filesize': size_bytes,
                         'url': download_url,
+                        'alt_title': traverse_obj(media_attributes, ('file_name', {str})),
                     })
 
             elif include_type == 'user':