[udemy] Remove unnecessary login/password encode

This is now covered by compat_urllib_parse_urlencode

youtube_dl/extractor/udemy.py

@@ -151,8 +151,8 @@ def is_logged(webpage):
         login_form = self._form_hidden_inputs('login-form', login_popup)
 
         login_form.update({
-            'email': username.encode('utf-8'),
-            'password': password.encode('utf-8'),
+            'email': username,
+            'password': password,
         })
 
         request = sanitized_Request(