✅(back) fix encoded JWT used in test suite

The last pyjwt update fix an issue related to headers disorered. This
fix changing the header order, the header hash is changing, so the
signature is changing too. To fix this we have to update encoded JWT in
our test.
See jpadilla/pyjwt#721

Author: lunika

src/backend/marsha/core/tests/test_api_video.py

@@ -4439,11 +4439,11 @@ def test_api_video_instructor_initiate_jitsi_live_with_token(self):
                         "interface_config_overwrite": {},
                         "room_name": str(video.pk),
                         "token": (
-                            "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9."
+                            "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9."
                             "eyJleHAiOjE2NTE2MjMwMDAsImlhdCI6MTY1MTYyMjQwMCwibW9kZXJhdG9yIjp0cnVl"
                             "LCJhdWQiOiJqaXRzaSIsImlzcyI6ImppdHNpX2FwcF9pZCIsInN1YiI6Im1lZXQuaml0"
                             "LnNpIiwicm9vbSI6IjI3YTIzZjUyLTMzNzktNDZhMi05NGZhLTY5N2I1OWNmZTNjNyJ9"
-                            ".LpHprY_P63wuKiIasYNev_LJmQJsPAWEfo0qz6MwoGc"
+                            ".XHsCRoAAGC4jp-hj80LGE8tNOi3V3efgPcqcXuBKHJI"
                         ),
                     }
                 },