* converted RetrieveDiagnosisKeysTransaction to Task

* cherry picked and solved access to the new task

* fixed background workers

* fixed background workers

* detekt ktlint unit test

* ktlint

* check cancel

* fixed flow

* fixed flow

* fixed flow

* fixed typo

* Make klint happy.

* Little refactoring to address PR comments (DI instead of static access).

Co-authored-by: harambasicluka <64483219+harambasicluka@users.noreply.github.com>
Co-authored-by: Matthias Urhahn <matthias.urhahn@sap.com>