🔥(backend) remove todo items

The Pylint job was failing due to those TODO items. In our make lint
command sequence, Pylint runs first. If it fails, Ruff won't run,
which is quite inconvenient.

I've extracted those TODOs into an issue for further review.

src/backend/core/api/serializers.py

@@ -134,6 +134,4 @@ class RoomSerializer(serializers.ModelSerializer):
 
         output["is_administrable"] = is_admin
 
-        # todo - pass properly livekit configuration
-
         return output

src/backend/core/api/viewsets.py

@@ -209,7 +209,6 @@ class RoomViewSet(
         user = self.request.user
 
         if user.is_authenticated:
-            # todo - simplify this queryset
             queryset = (
                 self.filter_queryset(self.get_queryset())
                 .filter(Q(users=user))

src/backend/core/utils.py

@@ -22,7 +22,6 @@ def generate_token(room: str, user, username: Optional[str] = None) -> str:
         str: The LiveKit JWT access token.
     """
 
-    # todo - define the video grants properly based on user and room.
     video_grants = VideoGrants(
         room=room,
         room_join=True,