Fixes an error handling in BugreportProgressService

Calls onError function when bugreport is finished and file is empty.

Bug: 174314124
Bug: 175287931
Test: atest BugreportReceiverTest
Change-Id: I4542568fd2d2ad1c75c7c3b223accca4995938a3
Merged-In: I4542568fd2d2ad1c75c7c3b223accca4995938a3
2 files changed