build: Actually remove the /api/class import

backend/src/main.ts

@@ -12,7 +12,6 @@ import { isAuthenticated, performLogin } from "./security/auth";
 import { LRequest } from "./types/express";
 
 import UserRouter from "./api/user";
-import ClassRouter from "./api/class";
 import LevelRouter from "./api/level";
 
 import { ITrackerDBModel } from "./models/tracker";