Updated in order to be used with NS7

[danirock99]

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• All existing tests are passing
• Tests for the changes are included

What is the current behavior?

Compatible with ES6 syntax.

What is the new behavior?

Added constructor for paypal-checkout files (with .ts extension)

Fixes/Implements/Closes #[Issue Number].