Fix logging

The logging logic used the checkedOptions directy, which means the logs
did not respect any special implicit opt-in cases. Instead of accessing
the checkedOptions, there are now dedicated fields in the BalState
object.
This also means there is no more passing through the checked options
anywhere and I removed a redundant call to determine the opt-in state
for the sender side.
Additional pure refactorings:
- use static imports for MODE_BACKGROUND_ACTIVITY_START_* constants.

Test: atest BackgroundActivityLaunchTest
Bug: 320558614
Change-Id: I8ffe2808a047eea4df17421897c7e269e3bafbfb