Use correct package name for monitor events

The currentPackage member variable in PFTBT is not necessary and is set
to the last package that was passed in to the constructor. Then all
events are sent with this package name even if they are for different
packages.

Bug: 396664485
Flag: EXEMPT Bugfix
Test: presubmit
Change-Id: Icd6c04399d6e5345a94dfdf4bb46e15928dcca7a