title: Add a close button in native barcode scanner
body: <p>I am trying to create a barcode scanner app, so i followed this <a href="https://ionicframework.com/docs/native/barcode-scanner/" rel="nofollow noreferrer">link in ionic</a> it woks fine but i need a close button on the camera screen so that i can close the camera if its not necessary 
  could someone help me with this</p>
  
  <p>my ionic info
  Ionic:</p>
  
  <p>ionic (Ionic CLI)  : 4.1.2
     Ionic Framework    : ionic-angular 3.9.2
     @ionic/app-scripts : 3.2.0</p>
  
  <p>Cordova:</p>
  
  <p>cordova (Cordova CLI) : 8.1.1 (cordova-lib@8.1.0)
     Cordova Platforms     : android 7.1.1
     Cordova Plugins       : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 2.1.4, (and 10 other plugins)</p>
  
  <p>System:</p>
  
  <p>NodeJS : v8.12.0
     npm    : 6.4.1</p>
  
  <p>phonegap-plugin-barcodescanner 8.0.0 "BarcodeScanner"</p>