Improve risklevel result data access performance (DEV) #1953

* Don't log all exposure windows on `RiskLevelTaskResult.toString()` due to performance impact when logging.

* Add RiskLevelResult flow optimized for just getting the latest two results.

* Share risk level result subscriptions.
The delay when switching from Home to RiskDetails fragment will be bridged and no re-loading necessary.

* Fix test regressions

* Remove test code.

* Introduce specific query for "latestAndLastSuccessful".
Add unit tests for SQL queries.

* Fix test regressions due to missing mocking.

* Address merge conflicts.

* Fix instrumentation tests not building.

Co-authored-by: Ralf Gehrer <ralfgehrer@users.noreply.github.com>