Optimize extract_info: no process=True for YouTube

For YT, processing separate videos greatly increases extract_info time,
but unnecessary when obtaining only track title.

For Yandex, processing is much faster, and we NEED it to get title.

backend/ydl_pool.py

@@ -36,6 +36,9 @@ create_ydl_fn = {
 
 ydl_fn_keys = create_ydl_fn.keys()
 
+# need process=True for track title in extract_info output
+NP_YDLS = {'yandex'}
+
 
 class Downloader:
 
@@ -51,6 +54,7 @@ class Downloader:
         }
 
         self.cur_ydl: YoutubeDL | None = None
+        self.cur_site = ''
 
         self.progress_cb = progress_cb
         self.lyrics_cb = lyrics_cb
@@ -71,6 +75,7 @@ class Downloader:
                 ydl.params['cookiefile'] = str(cookies)
 
         self.cur_ydl = ydl
+        self.cur_site = site
 
     def get_cur_ydl(self) -> YoutubeDL:
 
@@ -86,12 +91,13 @@ class Downloader:
             Downloader._target_get_playlist_items,
             self.get_cur_ydl(),
             url,
+            self.cur_site in NP_YDLS,
         )
 
     @staticmethod
-    def _target_get_playlist_items(ydl: YoutubeDL, url: str) -> list[str]:
+    def _target_get_playlist_items(ydl: YoutubeDL, url: str, process: bool) -> list[str]:
 
-        info = ydl.extract_info(url, download=False, process=True)
+        info = ydl.extract_info(url, download=False, process=process)
         if info is None:
             raise RuntimeError('ydl.extract_info returned None')
         return [