update imports for React 18

Change-Id: Ibc75ce532003a478b31d5d85d84c83a017262041
diff --git a/client/src/components/Header.js b/client/src/components/Header.js
index c2dc29e..0c3eda4 100644
--- a/client/src/components/Header.js
+++ b/client/src/components/Header.js
@@ -1,4 +1,4 @@
-import React, { useState } from 'react'
+import { useState } from 'react'
 import { Box, Button, Menu, MenuItem } from '@mui/material'
 import { useNavigate, useParams } from "react-router-dom"
 import authManager from '../AuthManager'