refactor(usePreviousPage): 필요없는 state 삭제 및 그 전 페이지만 저장하도록 수정

- 그전 페이지만 알면되므로 객체로 저장할 필요가 없고, 그전 페이지를 state로 관리할 필요가 없기에 수정했습니다.

frontend/src/hooks/usePreviousPage.ts

@@ -1,26 +1,13 @@
-import { useEffect, useState } from "react";
 import { useLocation, useNavigate } from "react-router-dom";
 
 import { ROUTE_PATHS_MAP } from "@constants/route";
 
-interface PreviousPages {
-  [key: string]: string;
-}
-
 const usePreviousPage = () => {
   const navigate = useNavigate();
   const location = useLocation();
-  const [previousPages, setPreviousPages] = useState<PreviousPages>({});
-
-  useEffect(() => {
-    setPreviousPages((prev) => ({
-      ...prev,
-      [location.pathname]: document.referrer,
-    }));
-  }, [location]);
+  const previousPage = document.referrer;
 
   const goBack = () => {
-    const previousPage = previousPages[location.pathname];
     const currentPage = location.pathname;
     const isPreviousPageMy = previousPage?.includes(ROUTE_PATHS_MAP.my);
     const isCurrentPageLogin = currentPage.includes(ROUTE_PATHS_MAP.login);