Rollback to Amazon SDK v1.0.3
Enqueue transactions before initialization
rejectTransaction() should not do anything

The assumption is that a bad transaction (hack) did not come from the
provider, and does not therefore require finalization.

If on the other hand, the verification service failed (network issues,
etc), we don't want to finalize the transaction and instead want to
be reminded later so that it can be verified again.
Include _error in storekit tx