[Marketplace][Payments] Test to purchase an app on Dev 

## Precoditions
- [x] Marketplace-dev app is installed on the test Firefox OS device
- [x] Marketplace-dev app has been successfully launched.
- [x]  Tester is logged in.
- [x] The payment flow has been triggered by clicking on the purchase button
- [x] Enter PIN screen has loaded


## Steps to test
- [x]  Enter valid PIN
- [x]  Confirm valid PIN
- [x] Click Continue


## Expected result:
- [x]  Confirm your mobile number screen from Bango loads