Fix TypeScript unused variable errors

server/routes/admin.ts

@@ -10,7 +10,7 @@ const router = Router();
 router.use(requireAuth);
 
 // Get all questionnaires
-router.get('/questionnaires', (req: Request, res: Response) => {
+router.get('/questionnaires', (_req: Request, res: Response) => {
   const questionnaires = questionnaireOps.getAll();
   res.json(questionnaires);
 });
@@ -207,7 +207,7 @@ router.delete('/activities/:id', (req: Request, res: Response) => {
 });
 
 // Get all users
-router.get('/users', (req: Request, res: Response) => {
+router.get('/users', (_req: Request, res: Response) => {
   const users = userOps.getAll();
   res.json(users);
 });