Align openapi specs to the actual API

api/funkwhale_api/instance/serializers.py

@@ -105,7 +105,7 @@ class MetadataSerializer(serializers.Serializer):
     funkwhaleSupportMessageEnabled = serializers.SerializerMethodField()
     instanceSupportMessage = serializers.SerializerMethodField()
     endpoints = EndpointsSerializer()
-    usage = serializers.SerializerMethodField(source="stats")
+    usage = MetadataUsageSerializer(source="stats", required=False)
 
     def get_private(self, obj) -> bool:
         return obj["preferences"].get("instance__nodeinfo_private")

api/funkwhale_api/instance/views.py

@@ -64,7 +64,9 @@ class NodeInfo(views.APIView):
     permission_classes = []
     authentication_classes = []
 
-    @extend_schema(responses=serializers.NodeInfo20Serializer)
+    @extend_schema(
+        responses=serializers.NodeInfo20Serializer, operation_id="getNodeInfo20"
+    )
     def get(self, request):
         pref = preferences.all()
         if (