[extractor/BiliIntl] Fix metadata extraction

Closes #4116

yt_dlp/utils.py

@@ -3216,7 +3216,11 @@ def fix_kv(m):
 
         return '"%s"' % v
 
+    def create_map(mobj):
+        return json.dumps(dict(json.loads(js_to_json(mobj.group(1) or '[]', vars=vars))))
+
     code = re.sub(r'new Date\((".+")\)', r'\g<1>', code)
+    code = re.sub(r'new Map\((\[.*?\])?\)', create_map, code)
 
     return re.sub(r'''(?sx)
         "(?:[^"\\]*(?:\\\\|\\['"nurtbfx/\n]))*[^"\\]*"|