[udemy] Improve course id v4 regex

youtube_dl/extractor/udemy.py

@@ -144,7 +144,7 @@ class UdemyIE(InfoExtractor):
         webpage = self._download_webpage(url, lecture_id)
 
         course_id = self._search_regex(
-            (r'data-course-id=["\'](\d+)', r'"id": (\d+)'),
+            (r'data-course-id=["\'](\d+)', r'"id"\s*:\s*(\d+)'),
             webpage, 'course id')
 
         try: