Bank Auth opens the native browser of the device

**Describe the bug**
When you use bank auth it takes away from the app and uses the device native browser

**To Reproduce**
Steps to reproduce the behavior:
1. Go to 'Bank Auth'
2. Click on '.Authenticate'
3. redirects to native browser

**Expected behavior**
Stays within the paystack-react-native-webview instead of taking away from the app
