fix: make PaymentRequest.abort actually return Promise<void> (#282)

* fix: make abort method on PaymentRequest actually return a Promise<void>, thereby properly cancelling event listeners

* chore: use single quotes

* chore: fix accidental removal of get shippingAddress getter

js/PaymentRequest/index.js

@@ -485,16 +485,13 @@ export default class PaymentRequest {
       }
 
       // Try to dismiss the UI
-      NativePayments.abort(err => {
-        if (err) {
-          return reject(new Error('InvalidStateError'));
-        }
-
-        this._closePaymentRequest();
-
-        // Return `undefined` as proposed in the spec.
-        return resolve(undefined);
-      });
+      NativePayments.abort()
+        .then((_bool) => {
+          this._closePaymentRequest();
+          // Return `undefined` as proposed in the spec.
+          return resolve(undefined);
+        })
+        .catch((_err) => reject(new Error('InvalidStateError')));
     });
   }