[WDR] Expand valid URL

Closes #1749

yt_dlp/extractor/wdr.py

@@ -22,7 +22,11 @@ from ..utils import (
 
 
 class WDRIE(InfoExtractor):
-    _VALID_URL = r'https?://deviceids-medp\.wdr\.de/ondemand/\d+/(?P<id>\d+)\.js'
+    _VALID_URL = r'''(?x)https?://
+        (?:deviceids-medp\.wdr\.de/ondemand/\d+/|
+           kinder\.wdr\.de/(?!mediathek/)[^#?]+-)
+        (?P<id>\d+)\.(?:js|assetjsonp)
+    '''
     _GEO_COUNTRIES = ['DE']
     _TEST = {
         'url': 'http://deviceids-medp.wdr.de/ondemand/155/1557833.js',