[ie] Extract from `media` elements in SMIL manifests (#8504)

Authored by: seproDev

yt_dlp/extractor/common.py

@@ -2341,7 +2341,9 @@ class InfoExtractor:
         imgs_count = 0
 
         srcs = set()
-        media = smil.findall(self._xpath_ns('.//video', namespace)) + smil.findall(self._xpath_ns('.//audio', namespace))
+        media = itertools.chain.from_iterable(
+            smil.findall(self._xpath_ns(arg, namespace))
+            for arg in ['.//video', './/audio', './/media'])
         for medium in media:
             src = medium.get('src')
             if not src or src in srcs: