Revert "[mailru] Fix extraction (closes #24530) (#25239)"

This reverts commit adc13b0.

youtube_dl/extractor/mailru.py

@@ -128,12 +128,6 @@ def _real_extract(self, url):
                 'http://api.video.mail.ru/videos/%s.json?new=1' % video_id,
                 video_id, 'Downloading video JSON')
 
-        headers = {}
-
-        video_key = self._get_cookies('https://my.mail.ru').get('video_key')
-        if video_key:
-            headers['Cookie'] = 'video_key=%s' % video_key.value
-
         formats = []
         for f in video_data['videos']:
             video_url = f.get('url')
@@ -146,7 +140,6 @@ def _real_extract(self, url):
                 'url': video_url,
                 'format_id': format_id,
                 'height': height,
-                'http_headers': headers,
             })
         self._sort_formats(formats)