[utils] Fix `find_element` by class (#11402)

Fix d710a6ca7c

Authored by: bashonly

yt_dlp/utils/traversal.py

@@ -391,14 +391,13 @@ def find_element(*, tag: str, html=False): ...
 def find_element(*, tag=None, id=None, cls=None, attr=None, value=None, html=False):
     # deliberately using `id=` and `cls=` for ease of readability
     assert tag or id or cls or (attr and value), 'One of tag, id, cls or (attr AND value) is required'
-    if not tag:
-        tag = r'[\w:.-]+'
+    ANY_TAG = r'[\w:.-]+'
 
     if attr and value:
         assert not cls, 'Cannot match both attr and cls'
         assert not id, 'Cannot match both attr and id'
         func = get_element_html_by_attribute if html else get_element_by_attribute
-        return functools.partial(func, attr, value, tag=tag)
+        return functools.partial(func, attr, value, tag=tag or ANY_TAG)
 
     elif cls:
         assert not id, 'Cannot match both cls and id'
@@ -408,7 +407,7 @@ def find_element(*, tag=None, id=None, cls=None, attr=None, value=None, html=Fal
 
     elif id:
         func = get_element_html_by_id if html else get_element_by_id
-        return functools.partial(func, id, tag=tag)
+        return functools.partial(func, id, tag=tag or ANY_TAG)
 
     index = int(bool(html))
     return lambda html: get_element_text_and_html_by_tag(tag, html)[index]