Update to ytdl-commit-6508688

Make default upload_/release_date a compat_str
https://github.com/ytdl-org/youtube-dl/commit/6508688e88c83bb811653083db9351702cd39a6a

Except:
* "[NDR] Overhaul NDR and NJoy extractors" https://github.com/ytdl-org/youtube-dl/pull/30531
    - https://github.com/ytdl-org/youtube-dl/commit/01824d275bfa7efbaca274b38c1ddc2b03f12f5d
    - https://github.com/ytdl-org/youtube-dl/commit/39a98b09a2acf50dc64bc41185be723b98e740b9
    - https://github.com/ytdl-org/youtube-dl/commit/f0a05a55c2ee512880546c056cfbec5ad3399798
    - https://github.com/ytdl-org/youtube-dl/commit/4186e817772d49d6f66b07c5ac8c248f026a6446

yt_dlp/extractor/videa.py

@@ -111,7 +111,6 @@ class VideaIE(InfoExtractor):
 
     def _real_extract(self, url):
         video_id = self._match_id(url)
-
         video_page = self._download_webpage(url, video_id)
 
         if 'videa.hu/player' in url:
@@ -146,7 +145,7 @@ class VideaIE(InfoExtractor):
                 compat_b64decode(b64_info), key), video_id)
 
         video = xpath_element(info, './video', 'video')
-        if not video:
+        if video is None:
             raise ExtractorError(xpath_element(
                 info, './error', fatal=True), expected=True)
         sources = xpath_element(
@@ -163,9 +162,9 @@ class VideaIE(InfoExtractor):
             source_exp = source.get('exp')
             if not (source_url and source_name):
                 continue
-            hash_value = None
-            if hash_values:
-                hash_value = xpath_text(hash_values, 'hash_value_' + source_name)
+            hash_value = (
+                xpath_text(hash_values, 'hash_value_' + source_name)
+                if hash_values is not None else None)
             if hash_value and source_exp:
                 source_url = update_url_query(source_url, {
                     'md5': hash_value,