Promise `finally` not working

[carlobeltrame]

Reportedly, on 1.x, the following does not work:

this.api.href(this.api.get(), 'invitation', {
        action: 'resend',
      }).then(postUrl => this.api.post(postUrl, {}))
        .finally(() => /* this is never called */)

This is probably caused by QueryablePromise, which we have removed in 2.x. We should write a test.