Remove mBalAllowedByPiCreatorWithHardening

Since BAL hardening is enabled on all trunk stable builds, the value of
mBalAllowedByPiCreatorWithHardening and mBalAllowedByPiCreator is the
same and logging both is unnecessary.

Test: atest BackgroundActivityStartControllerTests BackgroundActivityLaunchTest
Flag: EXEMPT refactoring
Change-Id: Ide580fb2798229fb24a8e174b08bc8dd00e31bf0