update imports for React 18

Change-Id: Ibc75ce532003a478b31d5d85d84c83a017262041
diff --git a/client/src/components/UsernameChooser.js b/client/src/components/UsernameChooser.js
index 2df96c6..7703639 100644
--- a/client/src/components/UsernameChooser.js
+++ b/client/src/components/UsernameChooser.js
@@ -1,4 +1,4 @@
-import React, { useEffect, useState } from 'react'
+import { useEffect, useState } from 'react'
 import usePromise from "react-fetch-hook/usePromise"
 import { InputAdornment, TextField } from '@mui/material'
 import { SearchRounded } from '@mui/icons-material'