refactor: remove duplicate express.json() middleware

Author: asoorm

server/src/index.ts

@@ -789,7 +789,6 @@ app.get("/config", originValidationMiddleware, authMiddleware, (req, res) => {
 });
 
 // OAuth Proxy Endpoints - for routing OAuth requests through the proxy to avoid CORS issues
-app.use(express.json()); // Ensure JSON body parsing is enabled
 
 /**
  * Proxy endpoint for OAuth Authorization Server Metadata Discovery