Ensure resultTo callback is always invoked.

Even if the broadcast is not enqueued for any
reason, we should ensure that resultTo callback
is invoked so that callers don't end up waiting
forever for the callback.

Bug: 284788269
Bug: 281722957
Test: manual
Change-Id: I89f14aec8b194da3ec35b0c9a6d465445ae9badb