add back button compenent

frontend/src/component/BackButton.js

+import React, { useEffect, useState } from "react";
+import { StyleSheet, View, Text, Pressable, ImageBackground, TouchableOpacity, Image, SafeAreaView } from 'react-native';
+import { useNavigation } from '@react-navigation/native';
+
+export default function BackButton(props) {
+
+    const navigation = useNavigation();
+    const { path } = props;
+
+    return (
+
+        <TouchableOpacity onPress={() => {
+            navigation.navigate(path);
+        }} style={{ flexDirection: "row", marginTop: -220, marginLeft: 10, width: "50%", height: "50%", }}>
+            <Image source={require('../assets/result/4.png')} resizeMode='contain' style={{ flex: .1 }} />
+        </TouchableOpacity>
+
+    )
+
+}