Cancel outstanding user consent request

When the end of bugreport generation is reached (i.e. bugreport has been
created) but the user has not responded to the user consent dialogue,
in that case we cancel the user consent request without copying
the file over to the caller.

Test: Tested by not replying to the user consent and checking the logs.
Bug: 128982019
Change-Id: Idd8cd2a62977ad592db9caf3febe89dd9917203f