refactor: 필요없는 코드 삭제 (#501)

frontend/src/App.tsx

@@ -1,19 +1,7 @@
 import { RouterProvider } from 'react-router-dom';
 import router from './router';
-import { useEffect } from 'react';
-import ReactGA from 'react-ga';
-import { createBrowserHistory as createHistory } from 'history';
 
 const App = () => {
-  const history = createHistory();
-
-  useEffect(() => {
-    ReactGA.initialize('G-RRSTX6Y61Y', { debug: true });
-    history.listen((location: any) => {
-      ReactGA.set({ page: location.pathname });
-      ReactGA.pageview(location.pathname);
-    });
-  }, []);
   return <RouterProvider router={router} />;
 };